class String
A String object has an arbitrary sequence of bytes, typically representing text or binary data. A String object may be created using String::new
or as literals.
String
objects differ from Symbol
objects in that Symbol
objects are designed to be used as identifiers, instead of text or data.
You can create a String object explicitly with:
You can convert certain objects to Strings with:
-
Method
String
.
Some String methods modify self
. Typically, a method whose name ends with !
modifies self
and returns self
; often a similarly named method (without the !
) returns a new string.
In general, if there exist both bang and non-bang version of method, the bang! mutates and the non-bang! does not. However, a method without a bang can also mutate, such as String#replace
.
Substitution Methods¶ ↑
These methods perform substitutions:
-
String#sub
: One substitution (or none); returns a new string. -
String#sub!
: One substitution (or none); returnsself
. -
String#gsub
: Zero or more substitutions; returns a new string. -
String#gsub!
: Zero or more substitutions; returnsself
.
Each of these methods takes:
-
A first argument,
pattern
(string or regexp), that specifies the substring(s) to be replaced. -
Either of these:
-
A second argument,
replacement
(string or hash), that determines the replacing string. -
A block that will determine the replacing string.
-
The examples in this section mostly use methods String#sub
and String#gsub
; the principles illustrated apply to all four substitution methods.
Argument pattern
Argument pattern
is commonly a regular expression:
s = 'hello' s.sub(/[aeiou]/, '*')# => "h*llo" s.gsub(/[aeiou]/, '*') # => "h*ll*" s.gsub(/[aeiou]/, '')# => "hll" s.sub(/ell/, 'al') # => "halo" s.gsub(/xyzzy/, '*') # => "hello" 'THX1138'.gsub(/\d+/, '00') # => "THX00"
When pattern
is a string, all its characters are treated as ordinary characters (not as regexp special characters):
'THX1138'.gsub('\d+', '00') # => "THX1138"
String replacement
If replacement
is a string, that string will determine the replacing string that is to be substituted for the matched text.
Each of the examples above uses a simple string as the replacing string.
String replacement
may contain back-references to the pattern’s captures:
-
\n
(n a non-negative integer) refers to$n
. -
\k<name>
refers to the named capturename
.
See Regexp
for details.
Note that within the string replacement
, a character combination such as $&
is treated as ordinary text, and not as a special match variable. However, you may refer to some special match variables using these combinations:
-
\&
and\0
correspond to$&
, which contains the complete matched text. -
\'
corresponds to$'
, which contains string after match. -
\`
corresponds to$`
, which contains string before match. -
\+
corresponds to$+
, which contains last capture group.
See Regexp
for details.
Note that \\
is interpreted as an escape, i.e., a single backslash.
Note also that a string literal consumes backslashes. See String Literals for details about string literals.
A back-reference is typically preceded by an additional backslash. For example, if you want to write a back-reference \&
in replacement
with a double-quoted string literal, you need to write "..\\&.."
.
If you want to write a non-back-reference string \&
in replacement
, you need first to escape the backslash to prevent this method from interpreting it as a back-reference, and then you need to escape the backslashes again to prevent a string literal from consuming them: "..\\\\&.."
.
You may want to use the block form to avoid a lot of backslashes.
Hash replacement
If argument replacement
is a hash, and pattern
matches one of its keys, the replacing string is the value for that key:
h = {'foo' => 'bar', 'baz' => 'bat'} 'food'.sub('foo', h) # => "bard"
Note that a symbol key does not match:
h = {foo: 'bar', baz: 'bat'} 'food'.sub('foo', h) # => "d"
Block
In the block form, the current match string is passed to the block; the block’s return value becomes the replacing string:
s = '@' '1234'.gsub(/\d/) {|match| s.succ! } # => "ABCD"
Special match variables such as $1
, $2
, $`
, $&
, and $'
are set appropriately.
Whitespace in Strings¶ ↑
In class String, whitespace is defined as a contiguous sequence of characters consisting of any mixture of the following:
-
NL (null):
"\x00"
,"\u0000"
. -
HT (horizontal tab):
"\x09"
,"\t"
. -
LF (line feed):
"\x0a"
,"\n"
. -
VT (vertical tab):
"\x0b"
,"\v"
. -
FF (form feed):
"\x0c"
,"\f"
. -
CR (carriage return):
"\x0d"
,"\r"
. -
SP (space):
"\x20"
," "
.
Whitespace is relevant for these methods:
String Slices¶ ↑
A slice of a string is a substring that is selected by certain criteria.
These instance methods make use of slicing:
-
String#[]
(also aliased asString#slice
) returns a slice copied fromself
. -
String#[]=
returns a copy ofself
with a slice replaced. -
String#slice!
returnsself
with a slice removed.
Each of the above methods takes arguments that determine the slice to be copied or replaced.
The arguments have several forms. For string string
, the forms are:
-
string[index]
. -
string[start, length]
. -
string[range]
. -
string[regexp, capture = 0]
. -
string[substring]
.
string[index]
When non-negative integer argument index
is given, the slice is the 1-character substring found in self
at character offset index
:
'bar'[0] # => "b" 'bar'[2] # => "r" 'bar'[20] # => nil 'тест'[2] # => "с" 'こんにちは'[4] # => "は"
When negative integer index
is given, the slice begins at the offset given by counting backward from the end of self
:
'bar'[-3] # => "b" 'bar'[-1] # => "r" 'bar'[-20] # => nil
string[start, length]
When non-negative integer arguments start
and length
are given, the slice begins at character offset start
, if it exists, and continues for length
characters, if available:
'foo'[0, 2] # => "fo" 'тест'[1, 2] # => "ес" 'こんにちは'[2, 2] # => "にち" # Zero length. 'foo'[2, 0] # => "" # Length not entirely available. 'foo'[1, 200] # => "oo" # Start out of range. 'foo'[4, 2] # => nil
Special case: if start
is equal to the length of self
, the slice is a new empty string:
'foo'[3, 2] # => "" 'foo'[3, 200] # => ""
When negative start
and non-negative length
are given, the slice beginning is determined by counting backward from the end of self
, and the slice continues for length
characters, if available:
'foo'[-2, 2] # => "oo" 'foo'[-2, 200] # => "oo" # Start out of range. 'foo'[-4, 2] # => nil
When negative length
is given, there is no slice:
'foo'[1, -1] # => nil 'foo'[-2, -1] # => nil
string[range]
When Range
argument range
is given, creates a substring of string
using the indices in range
. The slice is then determined as above:
'foo'[0..1] # => "fo" 'foo'[0, 2] # => "fo" 'foo'[2...2] # => "" 'foo'[2, 0] # => "" 'foo'[1..200] # => "oo" 'foo'[1, 200] # => "oo" 'foo'[4..5] # => nil 'foo'[4, 2] # => nil 'foo'[-4..-3] # => nil 'foo'[-4, 2] # => nil 'foo'[3..4] # => "" 'foo'[3, 2] # => "" 'foo'[-2..-1] # => "oo" 'foo'[-2, 2] # => "oo" 'foo'[-2..197] # => "oo" 'foo'[-2, 200] # => "oo"
string[regexp, capture = 0]
When the Regexp
argument regexp
is given, and the capture
argument is 0
, the slice is the first matching substring found in self
:
'foo'[/o/] # => "o" 'foo'[/x/] # => nil s = 'hello there' s[/[aeiou](.)\1/] # => "ell" s[/[aeiou](.)\1/, 0] # => "ell"
If argument capture
is given and not 0
, it should be either an capture group index (integer) or a capture group name (string or symbol); the slice is the specified capture (see Groups and Captures at Regexp
):
s = 'hello there' s[/[aeiou](.)\1/, 1] # => "l" s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, "non_vowel"] # => "l" s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, :vowel] # => "e"
If an invalid capture group index is given, there is no slice. If an invalid capture group name is given, IndexError
is raised.
string[substring]
When the single String argument substring
is given, returns the substring from self
if found, otherwise nil
:
'foo'['oo'] # => "oo" 'foo'['xx'] # => nil
What’s Here¶ ↑
First, what’s elsewhere. Class String:
-
Inherits from class Object.
-
Includes module Comparable.
Here, class String provides methods that are useful for:
Methods for Creating a String¶ ↑
-
::new
: Returns a new string. -
::try_convert
: Returns a new string created from a given object.
Methods for a Frozen/Unfrozen String
¶ ↑
-
+@
: Returns a string that is not frozen:self
, if not frozen;self.dup
otherwise. -
-@
: Returns a string that is frozen:self
, if already frozen;self.freeze
otherwise. -
freeze
: Freezesself
, if not already frozen; returnsself
.
Methods for Querying¶ ↑
Counts
-
empty?
: Returnstrue
ifself.length
is zero;false
otherwise. -
bytesize
: Returns the count of bytes. -
count
: Returns the count of substrings matching given strings.
Substrings
-
#=~: Returns the index of the first substring that matches a given
Regexp
or other object; returnsnil
if no match is found. -
index
: Returns the index of the first occurrence of a given substring; returnsnil
if none found. -
rindex
: Returns the index of the last occurrence of a given substring; returnsnil
if none found. -
include?
: Returnstrue
if the string contains a given substring;false
otherwise. -
match
: Returns aMatchData
object if the string matches a givenRegexp
;nil
otherwise. -
match?
: Returnstrue
if the string matches a givenRegexp
;false
otherwise. -
start_with?
: Returnstrue
if the string begins with any of the given substrings. -
end_with?
: Returnstrue
if the string ends with any of the given substrings.
Encodings
-
encoding
: Returns theEncoding
object that represents the encoding of the string. -
unicode_normalized?
: Returnstrue
if the string is in Unicode normalized form;false
otherwise. -
valid_encoding?
: Returnstrue
if the string contains only characters that are valid for its encoding. -
ascii_only?
: Returnstrue
if the string has only ASCII characters;false
otherwise.
Other
-
sum
: Returns a basic checksum for the string: the sum of each byte. -
hash
: Returns the integer hash code.
Methods for Comparing¶ ↑
-
==
,===
: Returnstrue
if a given other string has the same content asself
. -
eql?
: Returnstrue
if the content is the same as the given other string. -
#<=>: Returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger than
self
. -
casecmp
: Ignoring case, returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger thanself
. -
casecmp?
: Returnstrue
if the string is equal to a given string after Unicode case folding;false
otherwise.
Methods for Modifying a String¶ ↑
Each of these methods modifies self
.
Insertion
-
insert
: Returnsself
with a given string inserted at a given offset. -
<<
: Returnsself
concatenated with a given string or integer.
Substitution
-
sub!
: Replaces the first substring that matches a given pattern with a given replacement string; returnsself
if any changes,nil
otherwise. -
gsub!
: Replaces each substring that matches a given pattern with a given replacement string; returnsself
if any changes,nil
otherwise. -
succ!
,next!
: Returnsself
modified to become its own successor. -
replace
: Returnsself
with its entire content replaced by a given string. -
reverse!
: Returnsself
with its characters in reverse order. -
setbyte
: Sets the byte at a given integer offset to a given value; returns the argument. -
tr!
: Replaces specified characters inself
with specified replacement characters; returnsself
if any changes,nil
otherwise. -
tr_s!
: Replaces specified characters inself
with specified replacement characters, removing duplicates from the substrings that were modified; returnsself
if any changes,nil
otherwise.
Casing
-
capitalize!
: Upcases the initial character and downcases all others; returnsself
if any changes,nil
otherwise. -
downcase!
: Downcases all characters; returnsself
if any changes,nil
otherwise. -
upcase!
: Upcases all characters; returnsself
if any changes,nil
otherwise. -
swapcase!
: Upcases each downcase character and downcases each upcase character; returnsself
if any changes,nil
otherwise.
Encoding
-
encode!
: Returnsself
with all characters transcoded from one given encoding into another. -
unicode_normalize!
: Unicode-normalizesself
; returnsself
. -
scrub!
: Replaces each invalid byte with a given character; returnsself
. -
force_encoding
: Changes the encoding to a given encoding; returnsself
.
Deletion
-
clear
: Removes all content, so thatself
is empty; returnsself
. -
slice!
,[]=
: Removes a substring determined by a given index, start/length, range, regexp, or substring. -
squeeze!
: Removes contiguous duplicate characters; returnsself
. -
delete!
: Removes characters as determined by the intersection of substring arguments. -
lstrip!
: Removes leading whitespace; returnsself
if any changes,nil
otherwise. -
rstrip!
: Removes trailing whitespace; returnsself
if any changes,nil
otherwise. -
strip!
: Removes leading and trailing whitespace; returnsself
if any changes,nil
otherwise. -
chomp!
: Removes trailing record separator, if found; returnsself
if any changes,nil
otherwise. -
chop!
: Removes trailing newline characters if found; otherwise removes the last character; returnsself
if any changes,nil
otherwise.
Methods for Converting to New String¶ ↑
Each of these methods returns a new String based on self
, often just a modified copy of self
.
Extension
-
*
: Returns the concatenation of multiple copies ofself
, -
+
: Returns the concatenation ofself
and a given other string. -
center
: Returns a copy ofself
centered between pad substring. -
concat
: Returns the concatenation ofself
with given other strings. -
prepend
: Returns the concatenation of a given other string withself
. -
ljust
: Returns a copy ofself
of a given length, right-padded with a given other string. -
rjust
: Returns a copy ofself
of a given length, left-padded with a given other string.
Encoding
-
b
: Returns a copy ofself
with ASCII-8BIT encoding. -
scrub
: Returns a copy ofself
with each invalid byte replaced with a given character. -
unicode_normalize
: Returns a copy ofself
with each character Unicode-normalized. -
encode
: Returns a copy ofself
with all characters transcoded from one given encoding into another.
Substitution
-
dump
: Returns a copy ofself
with all non-printing characters replaced by xHH notation and all special characters escaped. -
undump
: Returns a copy ofself
with all\xNN
notation replace by\uNNNN
notation and all escaped characters unescaped. -
sub
: Returns a copy ofself
with the first substring matching a given pattern replaced with a given replacement string;. -
gsub
: Returns a copy ofself
with each substring that matches a given pattern replaced with a given replacement string. -
succ
,next
: Returns the string that is the successor toself
. -
reverse
: Returns a copy ofself
with its characters in reverse order. -
tr
: Returns a copy ofself
with specified characters replaced with specified replacement characters. -
tr_s
: Returns a copy ofself
with specified characters replaced with specified replacement characters, removing duplicates from the substrings that were modified. -
%
: Returns the string resulting from formatting a given object intoself
Casing
-
capitalize
: Returns a copy ofself
with the first character upcased and all other characters downcased. -
downcase
: Returns a copy ofself
with all characters downcased. -
upcase
: Returns a copy ofself
with all characters upcased. -
swapcase
: Returns a copy ofself
with all upcase characters downcased and all downcase characters upcased.
Deletion
-
delete
: Returns a copy ofself
with characters removed -
delete_prefix
: Returns a copy ofself
with a given prefix removed. -
delete_suffix
: Returns a copy ofself
with a given suffix removed. -
lstrip
: Returns a copy ofself
with leading whitespace removed. -
rstrip
: Returns a copy ofself
with trailing whitespace removed. -
strip
: Returns a copy ofself
with leading and trailing whitespace removed. -
chomp
: Returns a copy ofself
with a trailing record separator removed, if found. -
chop
: Returns a copy ofself
with trailing newline characters or the last character removed. -
squeeze
: Returns a copy ofself
with contiguous duplicate characters removed. -
[]
,slice
: Returns a substring determined by a given index, start/length, or range, or string. -
byteslice
: Returns a substring determined by a given index, start/length, or range. -
chr
: Returns the first character.
Duplication
-
to_s
, $to_str: Ifself
is a subclass of String, returnsself
copied into a String; otherwise, returnsself
.
Methods for Converting to Non-String¶ ↑
Each of these methods converts the contents of self
to a non-String.
Characters, Bytes, and Clusters
-
bytes
: Returns an array of the bytes inself
. -
chars
: Returns an array of the characters inself
. -
codepoints
: Returns an array of the integer ordinals inself
. -
getbyte
: Returns an integer byte as determined by a given index. -
grapheme_clusters
: Returns an array of the grapheme clusters inself
.
Splitting
-
lines
: Returns an array of the lines inself
, as determined by a given record separator. -
partition
: Returns a 3-element array determined by the first substring that matches a given substring or regexp, -
rpartition
: Returns a 3-element array determined by the last substring that matches a given substring or regexp, -
split
: Returns an array of substrings determined by a given delimiter – regexp or string – or, if a block given, passes those substrings to the block.
Matching
-
scan
: Returns an array of substrings matching a given regexp or string, or, if a block given, passes each matching substring to the block. -
unpack
: Returns an array of substrings extracted fromself
according to a given format. -
unpack1
: Returns the first substring extracted fromself
according to a given format.
Numerics
-
hex
: Returns the integer value of the leading characters, interpreted as hexadecimal digits. -
oct
: Returns the integer value of the leading characters, interpreted as octal digits. -
ord
: Returns the integer ordinal of the first character inself
. -
to_i
: Returns the integer value of leading characters, interpreted as an integer. -
to_f
: Returns the floating-point value of leading characters, interpreted as a floating-point number.
Strings and Symbols
-
inspect
: Returns copy ofself
, enclosed in double-quotes, with special characters escaped.
Methods for Iterating¶ ↑
-
each_byte
: Calls the given block with each successive byte inself
. -
each_char
: Calls the given block with each successive character inself
. -
each_codepoint
: Calls the given block with each successive integer codepoint inself
. -
each_grapheme_cluster
: Calls the given block with each successive grapheme cluster inself
. -
each_line
: Calls the given block with each successive line inself
, as determined by a given record separator. -
upto
: Calls the given block with each string value returned by successive calls tosucc
.
Public Class Methods
Returns a new String that is a copy of string
.
With no arguments, returns the empty string with the Encoding
ASCII-8BIT
:
s = String.new s # => "" s.encoding # => #<Encoding:ASCII-8BIT>
With optional argument string
and no keyword arguments, returns a copy of string
with the same encoding:
String.new('foo') # => "foo" String.new('тест') # => "тест" String.new('こんにちは') # => "こんにちは"
(Unlike String.new, a string literal like ''
or a here document literal always has script encoding.)
With optional keyword argument encoding
, returns a copy of string
with the specified encoding; the encoding
may be an Encoding
object, an encoding name, or an encoding name alias:
String.new('foo', encoding: Encoding::US_ASCII).encoding # => #<Encoding:US-ASCII> String.new('foo', encoding: 'US-ASCII').encoding # => #<Encoding:US-ASCII> String.new('foo', encoding: 'ASCII').encoding # => #<Encoding:US-ASCII>
The given encoding need not be valid for the string’s content, and that validity is not checked:
s = String.new('こんにちは', encoding: 'ascii') s.valid_encoding? # => false
But the given encoding
itself is checked:
String.new('foo', encoding: 'bar') # Raises ArgumentError.
With optional keyword argument capacity
, returns a copy of string
(or an empty string, if string
is not given); the given capacity
is advisory only, and may or may not set the size of the internal buffer, which may in turn affect performance:
String.new(capacity: 1) String.new('foo', capacity: 4096)
The string
, encoding
, and capacity
arguments may all be used together:
String.new('hello', encoding: 'UTF-8', capacity: 25)
static VALUE rb_str_init(int argc, VALUE *argv, VALUE str) { static ID keyword_ids[2]; VALUE orig, opt, venc, vcapa; VALUE kwargs[2]; rb_encoding *enc = 0; int n; if (!keyword_ids[0]) { keyword_ids[0] = rb_id_encoding(); CONST_ID(keyword_ids[1], "capacity"); } n = rb_scan_args(argc, argv, "01:", &orig, &opt); if (!NIL_P(opt)) { rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs); venc = kwargs[0]; vcapa = kwargs[1]; if (!UNDEF_P(venc) && !NIL_P(venc)) { enc = rb_to_encoding(venc); } if (!UNDEF_P(vcapa) && !NIL_P(vcapa)) { long capa = NUM2LONG(vcapa); long len = 0; int termlen = enc ? rb_enc_mbminlen(enc) : 1; if (capa < STR_BUF_MIN_SIZE) { capa = STR_BUF_MIN_SIZE; } if (n == 1) { StringValue(orig); len = RSTRING_LEN(orig); if (capa < len) { capa = len; } if (orig == str) n = 0; } str_modifiable(str); if (STR_EMBED_P(str) || FL_TEST(str, STR_SHARED|STR_NOFREE)) { /* make noembed always */ const size_t size = (size_t)capa + termlen; const char *const old_ptr = RSTRING_PTR(str); const size_t osize = RSTRING_LEN(str) + TERM_LEN(str); char *new_ptr = ALLOC_N(char, size); if (STR_EMBED_P(str)) RUBY_ASSERT(osize <= str_embed_capa(str)); memcpy(new_ptr, old_ptr, osize < size ? osize : size); FL_UNSET_RAW(str, STR_SHARED|STR_NOFREE); RSTRING(str)->as.heap.ptr = new_ptr; } else if (STR_HEAP_SIZE(str) != (size_t)capa + termlen) { SIZED_REALLOC_N(RSTRING(str)->as.heap.ptr, char, (size_t)capa + termlen, STR_HEAP_SIZE(str)); } STR_SET_LEN(str, len); TERM_FILL(&RSTRING(str)->as.heap.ptr[len], termlen); if (n == 1) { memcpy(RSTRING(str)->as.heap.ptr, RSTRING_PTR(orig), len); rb_enc_cr_str_exact_copy(str, orig); } FL_SET(str, STR_NOEMBED); RSTRING(str)->as.heap.aux.capa = capa; } else if (n == 1) { rb_str_replace(str, orig); } if (enc) { rb_enc_associate(str, enc); ENC_CODERANGE_CLEAR(str); } } else if (n == 1) { rb_str_replace(str, orig); } return str; }
If object
is a String object, returns object
.
Otherwise if object
responds to :to_str
, calls object.to_str
and returns the result.
Returns nil
if object
does not respond to :to_str
.
Raises an exception unless object.to_str
returns a String object.
static VALUE rb_str_s_try_convert(VALUE dummy, VALUE str) { return rb_check_string_type(str); }
Public Instance Methods
Returns the result of formatting object
into the format specification self
(see Kernel#sprintf
for formatting details):
"%05d" % 123 # => "00123"
If self
contains multiple substitutions, object
must be an Array
or Hash
containing the values to be substituted:
"%-5s: %016x" % [ "ID", self.object_id ] # => "ID : 00002b054ec93168" "foo = %{foo}" % {foo: 'bar'} # => "foo = bar" "foo = %{foo}, baz = %{baz}" % {foo: 'bar', baz: 'bat'} # => "foo = bar, baz = bat"
static VALUE rb_str_format_m(VALUE str, VALUE arg) { VALUE tmp = rb_check_array_type(arg); if (!NIL_P(tmp)) { return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str); } return rb_str_format(1, &arg, str); }
Returns a new String containing integer
copies of self
:
"Ho! " * 3 # => "Ho! Ho! Ho! " "Ho! " * 0 # => ""
VALUE rb_str_times(VALUE str, VALUE times) { VALUE str2; long n, len; char *ptr2; int termlen; if (times == INT2FIX(1)) { return str_duplicate(rb_cString, str); } if (times == INT2FIX(0)) { str2 = str_alloc_embed(rb_cString, 0); rb_enc_copy(str2, str); return str2; } len = NUM2LONG(times); if (len < 0) { rb_raise(rb_eArgError, "negative argument"); } if (RSTRING_LEN(str) == 1 && RSTRING_PTR(str)[0] == 0) { if (STR_EMBEDDABLE_P(len, 1)) { str2 = str_alloc_embed(rb_cString, len + 1); memset(RSTRING_PTR(str2), 0, len + 1); } else { str2 = str_alloc_heap(rb_cString); RSTRING(str2)->as.heap.aux.capa = len; RSTRING(str2)->as.heap.ptr = ZALLOC_N(char, (size_t)len + 1); } STR_SET_LEN(str2, len); rb_enc_copy(str2, str); return str2; } if (len && LONG_MAX/len < RSTRING_LEN(str)) { rb_raise(rb_eArgError, "argument too big"); } len *= RSTRING_LEN(str); termlen = TERM_LEN(str); str2 = str_new0(rb_cString, 0, len, termlen); ptr2 = RSTRING_PTR(str2); if (len) { n = RSTRING_LEN(str); memcpy(ptr2, RSTRING_PTR(str), n); while (n <= len/2) { memcpy(ptr2 + n, ptr2, n); n *= 2; } memcpy(ptr2 + n, ptr2, len-n); } STR_SET_LEN(str2, len); TERM_FILL(&ptr2[len], termlen); rb_enc_cr_str_copy_for_substr(str2, str); return str2; }
Returns a new String containing other_string
concatenated to self
:
"Hello from " + self.to_s # => "Hello from main"
VALUE rb_str_plus(VALUE str1, VALUE str2) { VALUE str3; rb_encoding *enc; char *ptr1, *ptr2, *ptr3; long len1, len2; int termlen; StringValue(str2); enc = rb_enc_check_str(str1, str2); RSTRING_GETMEM(str1, ptr1, len1); RSTRING_GETMEM(str2, ptr2, len2); termlen = rb_enc_mbminlen(enc); if (len1 > LONG_MAX - len2) { rb_raise(rb_eArgError, "string size too big"); } str3 = str_new0(rb_cString, 0, len1+len2, termlen); ptr3 = RSTRING_PTR(str3); memcpy(ptr3, ptr1, len1); memcpy(ptr3+len1, ptr2, len2); TERM_FILL(&ptr3[len1+len2], termlen); ENCODING_CODERANGE_SET(str3, rb_enc_to_index(enc), ENC_CODERANGE_AND(ENC_CODERANGE(str1), ENC_CODERANGE(str2))); RB_GC_GUARD(str1); RB_GC_GUARD(str2); return str3; }
Returns self
if self
is not frozen.
Otherwise returns self.dup
, which is not frozen.
static VALUE str_uplus(VALUE str) { if (OBJ_FROZEN(str)) { return rb_str_dup(str); } else { return str; } }
Returns a frozen, possibly pre-existing copy of the string.
The returned String will be deduplicated as long as it does not have any instance variables set on it and is not a String
subclass.
Note that -string
variant is more convenient for defining constants:
FILENAME = -'config/database.yml'
while dedup
is better suitable for using the method in chains of calculations:
@url_list.concat(urls.map(&:dedup))
static VALUE str_uminus(VALUE str) { if (!BARE_STRING_P(str) && !rb_obj_frozen_p(str)) { str = rb_str_dup(str); } return rb_fstring(str); }
Concatenates object
to self
and returns self
:
s = 'foo' s << 'bar' # => "foobar" s # => "foobar"
If object
is an Integer
, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s << 33 # => "foo!"
Related: String#concat
, which takes multiple arguments.
VALUE rb_str_concat(VALUE str1, VALUE str2) { unsigned int code; rb_encoding *enc = STR_ENC_GET(str1); int encidx; if (RB_INTEGER_TYPE_P(str2)) { if (rb_num_to_uint(str2, &code) == 0) { } else if (FIXNUM_P(str2)) { rb_raise(rb_eRangeError, "%ld out of char range", FIX2LONG(str2)); } else { rb_raise(rb_eRangeError, "bignum out of char range"); } } else { return rb_str_append(str1, str2); } encidx = rb_ascii8bit_appendable_encoding_index(enc, code); if (encidx >= 0) { char buf[1]; buf[0] = (char)code; rb_str_cat(str1, buf, 1); if (encidx != rb_enc_to_index(enc)) { rb_enc_associate_index(str1, encidx); ENC_CODERANGE_SET(str1, ENC_CODERANGE_VALID); } } else { long pos = RSTRING_LEN(str1); int cr = ENC_CODERANGE(str1); int len; char *buf; switch (len = rb_enc_codelen(code, enc)) { case ONIGERR_INVALID_CODE_POINT_VALUE: rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc)); break; case ONIGERR_TOO_BIG_WIDE_CHAR_VALUE: case 0: rb_raise(rb_eRangeError, "%u out of char range", code); break; } buf = ALLOCA_N(char, len + 1); rb_enc_mbcput(code, buf, enc); if (rb_enc_precise_mbclen(buf, buf + len + 1, enc) != len) { rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc)); } rb_str_resize(str1, pos+len); memcpy(RSTRING_PTR(str1) + pos, buf, len); if (cr == ENC_CODERANGE_7BIT && code > 127) { cr = ENC_CODERANGE_VALID; } else if (cr == ENC_CODERANGE_BROKEN) { cr = ENC_CODERANGE_UNKNOWN; } ENC_CODERANGE_SET(str1, cr); } return str1; }
Compares self
and other_string
, returning:
-
-1 if
other_string
is larger. -
0 if the two are equal.
-
1 if
other_string
is smaller. -
nil
if the two are incomparable.
Examples:
'foo' <=> 'foo' # => 0 'foo' <=> 'food' # => -1 'food' <=> 'foo' # => 1 'FOO' <=> 'foo' # => -1 'foo' <=> 'FOO' # => 1 'foo' <=> 1 # => nil
static VALUE rb_str_cmp_m(VALUE str1, VALUE str2) { int result; VALUE s = rb_check_string_type(str2); if (NIL_P(s)) { return rb_invcmp(str1, str2); } result = rb_str_cmp(str1, s); return INT2FIX(result); }
Returns true
if object
has the same length and content; as self
; false
otherwise:
s = 'foo' s == 'foo' # => true s == 'food' # => false s == 'FOO' # => false
Returns false
if the two strings’ encodings are not compatible:
"\u{e4 f6 fc}".encode("ISO-8859-1") == ("\u{c4 d6 dc}") # => false
If object
is not an instance of String but responds to to_str
, then the two strings are compared using object.==
.
VALUE rb_str_equal(VALUE str1, VALUE str2) { if (str1 == str2) return Qtrue; if (!RB_TYPE_P(str2, T_STRING)) { if (!rb_respond_to(str2, idTo_str)) { return Qfalse; } return rb_equal(str2, str1); } return rb_str_eql_internal(str1, str2); }
Returns true
if object
has the same length and content; as self
; false
otherwise:
s = 'foo' s == 'foo' # => true s == 'food' # => false s == 'FOO' # => false
Returns false
if the two strings’ encodings are not compatible:
"\u{e4 f6 fc}".encode("ISO-8859-1") == ("\u{c4 d6 dc}") # => false
If object
is not an instance of String but responds to to_str
, then the two strings are compared using object.==
.
Returns the Integer
index of the first substring that matches the given regexp
, or nil
if no match found:
'foo' =~ /f/ # => 0 'foo' =~ /o/ # => 1 'foo' =~ /x/ # => nil
Note: also updates Global Variables at Regexp
.
If the given object
is not a Regexp
, returns the value returned by object =~ self
.
Note that string =~ regexp
is different from regexp =~ string
(see Regexp#=~):
number= nil "no. 9" =~ /(?<number>\d+)/ number # => nil (not assigned) /(?<number>\d+)/ =~ "no. 9" number #=> "9"
static VALUE rb_str_match(VALUE x, VALUE y) { switch (OBJ_BUILTIN_TYPE(y)) { case T_STRING: rb_raise(rb_eTypeError, "type mismatch: String given"); case T_REGEXP: return rb_reg_match(y, x); default: return rb_funcall(y, idEqTilde, 1, x); } }
Returns the substring of self
specified by the arguments. See examples at String Slices.
static VALUE rb_str_aref_m(int argc, VALUE *argv, VALUE str) { if (argc == 2) { if (RB_TYPE_P(argv[0], T_REGEXP)) { return rb_str_subpat(str, argv[0], argv[1]); } else { long beg = NUM2LONG(argv[0]); long len = NUM2LONG(argv[1]); return rb_str_substr(str, beg, len); } } rb_check_arity(argc, 1, 2); return rb_str_aref(str, argv[0]); }
Replaces all, some, or none of the contents of self
; returns new_string
. See String Slices.
A few examples:
s = 'foo' s[2] = 'rtune' # => "rtune" s # => "fortune" s[1, 5] = 'init' # => "init" s # => "finite" s[3..4] = 'al' # => "al" s # => "finale" s[/e$/] = 'ly' # => "ly" s # => "finally" s['lly'] = 'ncial' # => "ncial" s # => "financial"
static VALUE rb_str_aset_m(int argc, VALUE *argv, VALUE str) { if (argc == 3) { if (RB_TYPE_P(argv[0], T_REGEXP)) { rb_str_subpat_set(str, argv[0], argv[1], argv[2]); } else { rb_str_update(str, NUM2LONG(argv[0]), NUM2LONG(argv[1]), argv[2]); } return argv[2]; } rb_check_arity(argc, 2, 3); return rb_str_aset(str, argv[0], argv[1]); }
Returns true
if self
contains only ASCII characters, false
otherwise:
'abc'.ascii_only? # => true "abc\u{6666}".ascii_only? # => false
static VALUE rb_str_is_ascii_only_p(VALUE str) { int cr = rb_enc_str_coderange(str); return RBOOL(cr == ENC_CODERANGE_7BIT); }
Returns a copy of self
that has ASCII-8BIT encoding; the underlying bytes are not modified:
s = "\x99" s.encoding # => #<Encoding:UTF-8> t = s.b # => "\x99" t.encoding # => #<Encoding:ASCII-8BIT> s = "\u4095" # => "䂕" s.encoding # => #<Encoding:UTF-8> s.bytes # => [228, 130, 149] t = s.b # => "\xE4\x82\x95" t.encoding # => #<Encoding:ASCII-8BIT> t.bytes # => [228, 130, 149]
static VALUE rb_str_b(VALUE str) { VALUE str2; if (STR_EMBED_P(str)) { str2 = str_alloc_embed(rb_cString, RSTRING_LEN(str) + TERM_LEN(str)); } else { str2 = str_alloc_heap(rb_cString); } str_replace_shared_without_enc(str2, str); if (rb_enc_asciicompat(STR_ENC_GET(str))) { // BINARY strings can never be broken; they're either 7-bit ASCII or VALID. // If we know the receiver's code range then we know the result's code range. int cr = ENC_CODERANGE(str); switch (cr) { case ENC_CODERANGE_7BIT: ENC_CODERANGE_SET(str2, ENC_CODERANGE_7BIT); break; case ENC_CODERANGE_BROKEN: case ENC_CODERANGE_VALID: ENC_CODERANGE_SET(str2, ENC_CODERANGE_VALID); break; default: ENC_CODERANGE_CLEAR(str2); break; } } return str2; }
Returns the Integer
byte-based index of the first occurrence of the given substring
, or nil
if none found:
'foo'.byteindex('f') # => 0 'foo'.byteindex('o') # => 1 'foo'.byteindex('oo') # => 1 'foo'.byteindex('ooo') # => nil
Returns the Integer
byte-based index of the first match for the given Regexp
regexp
, or nil
if none found:
'foo'.byteindex(/f/) # => 0 'foo'.byteindex(/o/) # => 1 'foo'.byteindex(/oo/) # => 1 'foo'.byteindex(/ooo/) # => nil
Integer
argument offset
, if given, specifies the byte-based position in the string to begin the search:
'foo'.byteindex('o', 1) # => 1 'foo'.byteindex('o', 2) # => 2 'foo'.byteindex('o', 3) # => nil
If offset
is negative, counts backward from the end of self
:
'foo'.byteindex('o', -1) # => 2 'foo'.byteindex('o', -2) # => 1 'foo'.byteindex('o', -3) # => 1 'foo'.byteindex('o', -4) # => nil
If offset
does not land on character (codepoint) boundary, IndexError
is raised.
Related: String#index
, String#byterindex
.
static VALUE rb_str_byteindex_m(int argc, VALUE *argv, VALUE str) { VALUE sub; VALUE initpos; long pos; if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) { long slen = RSTRING_LEN(str); pos = NUM2LONG(initpos); if (pos < 0 ? (pos += slen) < 0 : pos > slen) { if (RB_TYPE_P(sub, T_REGEXP)) { rb_backref_set(Qnil); } return Qnil; } } else { pos = 0; } str_ensure_byte_pos(str, pos); if (RB_TYPE_P(sub, T_REGEXP)) { if (rb_reg_search(sub, str, pos, 0) >= 0) { VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = BEG(0); return LONG2NUM(pos); } } else { StringValue(sub); pos = rb_str_byteindex(str, sub, pos); if (pos >= 0) return LONG2NUM(pos); } return Qnil; }
Returns the Integer
byte-based index of the last occurrence of the given substring
, or nil
if none found:
'foo'.byterindex('f') # => 0 'foo'.byterindex('o') # => 2 'foo'.byterindex('oo') # => 1 'foo'.byterindex('ooo') # => nil
Returns the Integer
byte-based index of the last match for the given Regexp
regexp
, or nil
if none found:
'foo'.byterindex(/f/) # => 0 'foo'.byterindex(/o/) # => 2 'foo'.byterindex(/oo/) # => 1 'foo'.byterindex(/ooo/) # => nil
The last match means starting at the possible last position, not the last of longest matches.
'foo'.byterindex(/o+/) # => 2 $~ #=> #<MatchData "o">
To get the last longest match, needs to combine with negative lookbehind.
'foo'.byterindex(/(?<!o)o+/) # => 1 $~ #=> #<MatchData "oo">
Or String#byteindex
with negative lookforward.
'foo'.byteindex(/o+(?!.*o)/) # => 1 $~ #=> #<MatchData "oo">
Integer
argument offset
, if given and non-negative, specifies the maximum starting byte-based position in the
string to _end_ the search: 'foo'.byterindex('o', 0) # => nil 'foo'.byterindex('o', 1) # => 1 'foo'.byterindex('o', 2) # => 2 'foo'.byterindex('o', 3) # => 2
If offset
is a negative Integer
, the maximum starting position in the string to end the search is the sum of the string’s length and offset
:
'foo'.byterindex('o', -1) # => 2 'foo'.byterindex('o', -2) # => 1 'foo'.byterindex('o', -3) # => nil 'foo'.byterindex('o', -4) # => nil
If offset
does not land on character (codepoint) boundary, IndexError
is raised.
Related: String#byteindex
.
static VALUE rb_str_byterindex_m(int argc, VALUE *argv, VALUE str) { VALUE sub; VALUE initpos; long pos, len = RSTRING_LEN(str); if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) { pos = NUM2LONG(initpos); if (pos < 0 && (pos += len) < 0) { if (RB_TYPE_P(sub, T_REGEXP)) { rb_backref_set(Qnil); } return Qnil; } if (pos > len) pos = len; } else { pos = len; } str_ensure_byte_pos(str, pos); if (RB_TYPE_P(sub, T_REGEXP)) { if (rb_reg_search(sub, str, pos, 1) >= 0) { VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = BEG(0); return LONG2NUM(pos); } } else { StringValue(sub); pos = rb_str_byterindex(str, sub, pos); if (pos >= 0) return LONG2NUM(pos); } return Qnil; }
Returns an array of the bytes in self
:
'hello'.bytes # => [104, 101, 108, 108, 111] 'тест'.bytes # => [209, 130, 208, 181, 209, 129, 209, 130] 'こんにちは'.bytes # => [227, 129, 147, 227, 130, 147, 227, 129, 171, 227, 129, 161, 227, 129, 175]
static VALUE rb_str_bytes(VALUE str) { VALUE ary = WANTARRAY("bytes", RSTRING_LEN(str)); return rb_str_enumerate_bytes(str, ary); }
Returns the count of bytes (not characters) in self
:
'foo'.bytesize # => 3 'тест'.bytesize # => 8 'こんにちは'.bytesize # => 15
Contrast with String#length
:
'foo'.length # => 3 'тест'.length # => 4 'こんにちは'.length # => 5
VALUE rb_str_bytesize(VALUE str) { return LONG2NUM(RSTRING_LEN(str)); }
Returns a substring of self
, or nil
if the substring cannot be constructed.
With integer arguments index
and length
given, returns the substring beginning at the given index
of the given length
(if possible), or nil
if length
is negative or index
falls outside of self
:
s = '0123456789' # => "0123456789" s.byteslice(2) # => "2" s.byteslice(200) # => nil s.byteslice(4, 3) # => "456" s.byteslice(4, 30) # => "456789" s.byteslice(4, -1) # => nil s.byteslice(40, 2) # => nil
In either case above, counts backwards from the end of self
if index
is negative:
s = '0123456789' # => "0123456789" s.byteslice(-4) # => "6" s.byteslice(-4, 3) # => "678"
With Range
argument range
given, returns byteslice(range.begin, range.size)
:
s = '0123456789' # => "0123456789" s.byteslice(4..6) # => "456" s.byteslice(-6..-4) # => "456" s.byteslice(5..2) # => "" # range.size is zero. s.byteslice(40..42) # => nil
In all cases, a returned string has the same encoding as self
:
s.encoding # => #<Encoding:UTF-8> s.byteslice(4).encoding # => #<Encoding:UTF-8>
static VALUE rb_str_byteslice(int argc, VALUE *argv, VALUE str) { if (argc == 2) { long beg = NUM2LONG(argv[0]); long len = NUM2LONG(argv[1]); return str_byte_substr(str, beg, len, TRUE); } rb_check_arity(argc, 1, 2); return str_byte_aref(str, argv[0]); }
Replaces some or all of the content of self
with str
, and returns self
. The portion of the string affected is determined using the same criteria as String#byteslice
, except that length
cannot be omitted. If the replacement string is not the same length as the text it is replacing, the string will be adjusted accordingly.
If str_index
and str_length
, or str_range
are given, the content of self
is replaced by str.byteslice(str_index, str_length) or str.byteslice(str_range); however the substring of str
is not allocated as a new string.
The form that take an Integer
will raise an IndexError
if the value is out of range; the Range
form will raise a RangeError
. If the beginning or ending offset does not land on character (codepoint) boundary, an IndexError
will be raised.
static VALUE rb_str_bytesplice(int argc, VALUE *argv, VALUE str) { long beg, len, vbeg, vlen; VALUE val; rb_encoding *enc; int cr; rb_check_arity(argc, 2, 5); if (!(argc == 2 || argc == 3 || argc == 5)) { rb_raise(rb_eArgError, "wrong number of arguments (given %d, expected 2, 3, or 5)", argc); } if (argc == 2 || (argc == 3 && !RB_INTEGER_TYPE_P(argv[0]))) { if (!rb_range_beg_len(argv[0], &beg, &len, RSTRING_LEN(str), 2)) { rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)", rb_builtin_class_name(argv[0])); } val = argv[1]; StringValue(val); if (argc == 2) { /* bytesplice(range, str) */ vbeg = 0; vlen = RSTRING_LEN(val); } else { /* bytesplice(range, str, str_range) */ if (!rb_range_beg_len(argv[2], &vbeg, &vlen, RSTRING_LEN(val), 2)) { rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)", rb_builtin_class_name(argv[2])); } } } else { beg = NUM2LONG(argv[0]); len = NUM2LONG(argv[1]); val = argv[2]; StringValue(val); if (argc == 3) { /* bytesplice(index, length, str) */ vbeg = 0; vlen = RSTRING_LEN(val); } else { /* bytesplice(index, length, str, str_index, str_length) */ vbeg = NUM2LONG(argv[3]); vlen = NUM2LONG(argv[4]); } } str_check_beg_len(str, &beg, &len); str_check_beg_len(val, &vbeg, &vlen); enc = rb_enc_check(str, val); str_modify_keep_cr(str); rb_str_update_1(str, beg, len, val, vbeg, vlen); rb_enc_associate(str, enc); cr = ENC_CODERANGE_AND(ENC_CODERANGE(str), ENC_CODERANGE(val)); if (cr != ENC_CODERANGE_BROKEN) ENC_CODERANGE_SET(str, cr); return str; }
Returns a string containing the characters in self
; the first character is upcased; the remaining characters are downcased:
s = 'hello World!' # => "hello World!" s.capitalize # => "Hello world!"
The casing may be affected by the given options
; see Case Mapping.
Related: String#capitalize!
.
static VALUE rb_str_capitalize(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE; VALUE ret; flags = check_case_options(argc, argv, flags); enc = str_true_enc(str); if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str; if (flags&ONIGENC_CASE_ASCII_ONLY) { ret = rb_str_new(0, RSTRING_LEN(str)); rb_str_ascii_casemap(str, ret, &flags, enc); } else { ret = rb_str_casemap(str, &flags, enc); } return ret; }
Upcases the first character in self
; downcases the remaining characters; returns self
if any changes were made, nil
otherwise:
s = 'hello World!' # => "hello World!" s.capitalize! # => "Hello world!" s # => "Hello world!" s.capitalize! # => nil
The casing may be affected by the given options
; see Case Mapping.
Related: String#capitalize
.
static VALUE rb_str_capitalize_bang(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE; flags = check_case_options(argc, argv, flags); str_modify_keep_cr(str); enc = str_true_enc(str); if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil; if (flags&ONIGENC_CASE_ASCII_ONLY) rb_str_ascii_casemap(str, str, &flags, enc); else str_shared_replace(str, rb_str_casemap(str, &flags, enc)); if (ONIGENC_CASE_MODIFIED&flags) return str; return Qnil; }
Compares self.downcase
and other_string.downcase
; returns:
-
-1 if
other_string.downcase
is larger. -
0 if the two are equal.
-
1 if
other_string.downcase
is smaller. -
nil
if the two are incomparable.
Examples:
'foo'.casecmp('foo') # => 0 'foo'.casecmp('food') # => -1 'food'.casecmp('foo') # => 1 'FOO'.casecmp('foo') # => 0 'foo'.casecmp('FOO') # => 0 'foo'.casecmp(1) # => nil
See Case Mapping.
Related: String#casecmp?
.
static VALUE rb_str_casecmp(VALUE str1, VALUE str2) { VALUE s = rb_check_string_type(str2); if (NIL_P(s)) { return Qnil; } return str_casecmp(str1, s); }
Returns true
if self
and other_string
are equal after Unicode case folding, otherwise false
:
'foo'.casecmp?('foo') # => true 'foo'.casecmp?('food') # => false 'food'.casecmp?('foo') # => false 'FOO'.casecmp?('foo') # => true 'foo'.casecmp?('FOO') # => true
Returns nil
if the two values are incomparable:
'foo'.casecmp?(1) # => nil
See Case Mapping.
Related: String#casecmp
.
static VALUE rb_str_casecmp_p(VALUE str1, VALUE str2) { VALUE s = rb_check_string_type(str2); if (NIL_P(s)) { return Qnil; } return str_casecmp_p(str1, s); }
Returns a centered copy of self
.
If integer argument size
is greater than the size (in characters) of self
, returns a new string of length size
that is a copy of self
, centered and padded on both ends with pad_string
:
'hello'.center(10) # => " hello " ' hello'.center(10) # => " hello " 'hello'.center(10, 'ab') # => "abhelloaba" 'тест'.center(10) # => " тест " 'こんにちは'.center(10) # => " こんにちは "
If size
is not greater than the size of self
, returns a copy of self
:
'hello'.center(5) # => "hello" 'hello'.center(1) # => "hello"
Related: String#ljust
, String#rjust
.
static VALUE rb_str_center(int argc, VALUE *argv, VALUE str) { return rb_str_justify(argc, argv, str, 'c'); }
Returns an array of the characters in self
:
'hello'.chars # => ["h", "e", "l", "l", "o"] 'тест'.chars # => ["т", "е", "с", "т"] 'こんにちは'.chars # => ["こ", "ん", "に", "ち", "は"]
static VALUE rb_str_chars(VALUE str) { VALUE ary = WANTARRAY("chars", rb_str_strlen(str)); return rb_str_enumerate_chars(str, ary); }
Returns a new string copied from self
, with trailing characters possibly removed:
When line_sep
is "\n"
, removes the last one or two characters if they are "\r"
, "\n"
, or "\r\n"
(but not "\n\r"
):
$/ # => "\n" "abc\r".chomp # => "abc" "abc\n".chomp # => "abc" "abc\r\n".chomp # => "abc" "abc\n\r".chomp # => "abc\n" "тест\r\n".chomp # => "тест" "こんにちは\r\n".chomp # => "こんにちは"
When line_sep
is ''
(an empty string), removes multiple trailing occurrences of "\n"
or "\r\n"
(but not "\r"
or "\n\r"
):
"abc\n\n\n".chomp('') # => "abc" "abc\r\n\r\n\r\n".chomp('') # => "abc" "abc\n\n\r\n\r\n\n\n".chomp('') # => "abc" "abc\n\r\n\r\n\r".chomp('') # => "abc\n\r\n\r\n\r" "abc\r\r\r".chomp('') # => "abc\r\r\r"
When line_sep
is neither "\n"
nor ''
, removes a single trailing line separator if there is one:
'abcd'.chomp('d') # => "abc" 'abcdd'.chomp('d') # => "abcd"
static VALUE rb_str_chomp(int argc, VALUE *argv, VALUE str) { VALUE rs = chomp_rs(argc, argv); if (NIL_P(rs)) return str_duplicate(rb_cString, str); return rb_str_subseq(str, 0, chompped_length(str, rs)); }
Like String#chomp
, but modifies self
in place; returns nil
if no modification made, self
otherwise.
static VALUE rb_str_chomp_bang(int argc, VALUE *argv, VALUE str) { VALUE rs; str_modifiable(str); if (RSTRING_LEN(str) == 0 && argc < 2) return Qnil; rs = chomp_rs(argc, argv); if (NIL_P(rs)) return Qnil; return rb_str_chomp_string(str, rs); }
Returns a new string copied from self
, with trailing characters possibly removed.
Removes "\r\n"
if those are the last two characters.
"abc\r\n".chop # => "abc" "тест\r\n".chop # => "тест" "こんにちは\r\n".chop # => "こんにちは"
Otherwise removes the last character if it exists.
'abcd'.chop # => "abc" 'тест'.chop # => "тес" 'こんにちは'.chop # => "こんにち" ''.chop # => ""
If you only need to remove the newline separator at the end of the string, String#chomp
is a better alternative.
static VALUE rb_str_chop(VALUE str) { return rb_str_subseq(str, 0, chopped_length(str)); }
Like String#chop
, but modifies self
in place; returns nil
if self
is empty, self
otherwise.
Related: String#chomp!
.
static VALUE rb_str_chop_bang(VALUE str) { str_modify_keep_cr(str); if (RSTRING_LEN(str) > 0) { long len; len = chopped_length(str); STR_SET_LEN(str, len); TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str)); if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) { ENC_CODERANGE_CLEAR(str); } return str; } return Qnil; }
Returns a string containing the first character of self
:
s = 'foo' # => "foo" s.chr # => "f"
static VALUE rb_str_chr(VALUE str) { return rb_str_substr(str, 0, 1); }
Removes the contents of self
:
s = 'foo' # => "foo" s.clear # => ""
static VALUE rb_str_clear(VALUE str) { str_discard(str); STR_SET_EMBED(str); STR_SET_LEN(str, 0); RSTRING_PTR(str)[0] = 0; if (rb_enc_asciicompat(STR_ENC_GET(str))) ENC_CODERANGE_SET(str, ENC_CODERANGE_7BIT); else ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID); return str; }
Returns an array of the codepoints in self
; each codepoint is the integer value for a character:
'hello'.codepoints # => [104, 101, 108, 108, 111] 'тест'.codepoints # => [1090, 1077, 1089, 1090] 'こんにちは'.codepoints # => [12371, 12435, 12395, 12385, 12399]
static VALUE rb_str_codepoints(VALUE str) { VALUE ary = WANTARRAY("codepoints", rb_str_strlen(str)); return rb_str_enumerate_codepoints(str, ary); }
Concatenates each object in objects
to self
and returns self
:
s = 'foo' s.concat('bar', 'baz') # => "foobarbaz" s # => "foobarbaz"
For each given object object
that is an Integer
, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"
Related: String#<<
, which takes a single argument.
static VALUE rb_str_concat_multi(int argc, VALUE *argv, VALUE str) { str_modifiable(str); if (argc == 1) { return rb_str_concat(str, argv[0]); } else if (argc > 1) { int i; VALUE arg_str = rb_str_tmp_new(0); rb_enc_copy(arg_str, str); for (i = 0; i < argc; i++) { rb_str_concat(arg_str, argv[i]); } rb_str_buf_append(str, arg_str); } return str; }
Returns the total number of characters in self
that are specified by the given selectors
(see Multiple Character Selectors):
a = "hello world" a.count "lo" #=> 5 a.count "lo", "o" #=> 2 a.count "hello", "^l" #=> 4 a.count "ej-m" #=> 4 "hello^world".count "\\^aeiou" #=> 4 "hello-world".count "a\\-eo" #=> 4 c = "hello world\\r\\n" c.count "\\" #=> 2 c.count "\\A" #=> 0 c.count "X-\\w" #=> 3
static VALUE rb_str_count(int argc, VALUE *argv, VALUE str) { char table[TR_TABLE_SIZE]; rb_encoding *enc = 0; VALUE del = 0, nodel = 0, tstr; char *s, *send; int i; int ascompat; size_t n = 0; rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS); tstr = argv[0]; StringValue(tstr); enc = rb_enc_check(str, tstr); if (argc == 1) { const char *ptstr; if (RSTRING_LEN(tstr) == 1 && rb_enc_asciicompat(enc) && (ptstr = RSTRING_PTR(tstr), ONIGENC_IS_ALLOWED_REVERSE_MATCH(enc, (const unsigned char *)ptstr, (const unsigned char *)ptstr+1)) && !is_broken_string(str)) { int clen; unsigned char c = rb_enc_codepoint_len(ptstr, ptstr+1, &clen, enc); s = RSTRING_PTR(str); if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0); send = RSTRING_END(str); while (s < send) { if (*(unsigned char*)s++ == c) n++; } return SIZET2NUM(n); } } tr_setup_table(tstr, table, TRUE, &del, &nodel, enc); for (i=1; i<argc; i++) { tstr = argv[i]; StringValue(tstr); enc = rb_enc_check(str, tstr); tr_setup_table(tstr, table, FALSE, &del, &nodel, enc); } s = RSTRING_PTR(str); if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0); send = RSTRING_END(str); ascompat = rb_enc_asciicompat(enc); while (s < send) { unsigned int c; if (ascompat && (c = *(unsigned char*)s) < 0x80) { if (table[c]) { n++; } s++; } else { int clen; c = rb_enc_codepoint_len(s, send, &clen, enc); if (tr_find(c, table, del, nodel)) { n++; } s += clen; } } return SIZET2NUM(n); }
Returns the string generated by calling crypt(3)
standard library function with str
and salt_str
, in this order, as its arguments. Please do not use this method any longer. It is legacy; provided only for backward compatibility with ruby scripts in earlier days. It is bad to use in contemporary programs for several reasons:
-
Behaviour of C’s
crypt(3)
depends on the OS it is run. The generated string lacks data portability. -
On some OSes such as Mac OS,
crypt(3)
never fails (i.e. silently ends up in unexpected results). -
On some OSes such as Mac OS,
crypt(3)
is not thread safe. -
So-called “traditional” usage of
crypt(3)
is very very very weak. According to its manpage, Linux’s traditionalcrypt(3)
output has only 2**56 variations; too easy to brute force today. And this is the default behaviour. -
In order to make things robust some OSes implement so-called “modular” usage. To go through, you have to do a complex build-up of the
salt_str
parameter, by hand. Failure in generation of a proper salt string tends not to yield any errors; typos in parameters are normally not detectable.-
For instance, in the following example, the second invocation of
String#crypt
is wrong; it has a typo in “round=” (lacks “s”). However the call does not fail and something unexpected is generated."foo".crypt("$5$rounds=1000$salt$") # OK, proper usage "foo".crypt("$5$round=1000$salt$") # Typo not detected
-
-
Even in the “modular” mode, some hash functions are considered archaic and no longer recommended at all; for instance module
$1$
is officially abandoned by its author: see phk.freebsd.dk/sagas/md5crypt_eol/ . For another instance module$3$
is considered completely broken: see the manpage of FreeBSD. -
On some OS such as Mac OS, there is no modular mode. Yet, as written above,
crypt(3)
on Mac OS never fails. This means even if you build up a proper salt string it generates a traditional DES hash anyways, and there is no way for you to be aware of."foo".crypt("$5$rounds=1000$salt$") # => "$5fNPQMxC5j6."
If for some reason you cannot migrate to other secure contemporary password hashing algorithms, install the string-crypt gem and require 'string/crypt'
to continue using it.
static VALUE rb_str_crypt(VALUE str, VALUE salt) { #ifdef HAVE_CRYPT_R VALUE databuf; struct crypt_data *data; # define CRYPT_END() ALLOCV_END(databuf) #else extern char *crypt(const char *, const char *); # define CRYPT_END() rb_nativethread_lock_unlock(&crypt_mutex.lock) #endif VALUE result; const char *s, *saltp; char *res; #ifdef BROKEN_CRYPT char salt_8bit_clean[3]; #endif StringValue(salt); mustnot_wchar(str); mustnot_wchar(salt); s = StringValueCStr(str); saltp = RSTRING_PTR(salt); if (RSTRING_LEN(salt) < 2 || !saltp[0] || !saltp[1]) { rb_raise(rb_eArgError, "salt too short (need >=2 bytes)"); } #ifdef BROKEN_CRYPT if (!ISASCII((unsigned char)saltp[0]) || !ISASCII((unsigned char)saltp[1])) { salt_8bit_clean[0] = saltp[0] & 0x7f; salt_8bit_clean[1] = saltp[1] & 0x7f; salt_8bit_clean[2] = '\0'; saltp = salt_8bit_clean; } #endif #ifdef HAVE_CRYPT_R data = ALLOCV(databuf, sizeof(struct crypt_data)); # ifdef HAVE_STRUCT_CRYPT_DATA_INITIALIZED data->initialized = 0; # endif res = crypt_r(s, saltp, data); #else crypt_mutex_initialize(); rb_nativethread_lock_lock(&crypt_mutex.lock); res = crypt(s, saltp); #endif if (!res) { int err = errno; CRYPT_END(); rb_syserr_fail(err, "crypt"); } result = rb_str_new_cstr(res); CRYPT_END(); return result; }
Returns a frozen, possibly pre-existing copy of the string.
The returned String will be deduplicated as long as it does not have any instance variables set on it and is not a String
subclass.
Note that -string
variant is more convenient for defining constants:
FILENAME = -'config/database.yml'
while dedup
is better suitable for using the method in chains of calculations:
@url_list.concat(urls.map(&:dedup))
Returns a copy of self
with characters specified by selectors
removed (see Multiple Character Selectors):
"hello".delete "l","lo" #=> "heo" "hello".delete "lo" #=> "he" "hello".delete "aeiou", "^e" #=> "hell" "hello".delete "ej-m" #=> "ho"
static VALUE rb_str_delete(int argc, VALUE *argv, VALUE str) { str = str_duplicate(rb_cString, str); rb_str_delete_bang(argc, argv, str); return str; }
Like String#delete
, but modifies self
in place. Returns self
if any changes were made, nil
otherwise.
static VALUE rb_str_delete_bang(int argc, VALUE *argv, VALUE str) { char squeez[TR_TABLE_SIZE]; rb_encoding *enc = 0; char *s, *send, *t; VALUE del = 0, nodel = 0; int modify = 0; int i, ascompat, cr; if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil; rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS); for (i=0; i<argc; i++) { VALUE s = argv[i]; StringValue(s); enc = rb_enc_check(str, s); tr_setup_table(s, squeez, i==0, &del, &nodel, enc); } str_modify_keep_cr(str); ascompat = rb_enc_asciicompat(enc); s = t = RSTRING_PTR(str); send = RSTRING_END(str); cr = ascompat ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID; while (s < send) { unsigned int c; int clen; if (ascompat && (c = *(unsigned char*)s) < 0x80) { if (squeez[c]) { modify = 1; } else { if (t != s) *t = c; t++; } s++; } else { c = rb_enc_codepoint_len(s, send, &clen, enc); if (tr_find(c, squeez, del, nodel)) { modify = 1; } else { if (t != s) rb_enc_mbcput(c, t, enc); t += clen; if (cr == ENC_CODERANGE_7BIT) cr = ENC_CODERANGE_VALID; } s += clen; } } TERM_FILL(t, TERM_LEN(str)); STR_SET_LEN(str, t - RSTRING_PTR(str)); ENC_CODERANGE_SET(str, cr); if (modify) return str; return Qnil; }
Returns a copy of self
with leading substring prefix
removed:
'hello'.delete_prefix('hel') # => "lo" 'hello'.delete_prefix('llo') # => "hello" 'тест'.delete_prefix('те') # => "ст" 'こんにちは'.delete_prefix('こん') # => "にちは"
Related: String#delete_prefix!
, String#delete_suffix
.
static VALUE rb_str_delete_prefix(VALUE str, VALUE prefix) { long prefixlen; prefixlen = deleted_prefix_length(str, prefix); if (prefixlen <= 0) return str_duplicate(rb_cString, str); return rb_str_subseq(str, prefixlen, RSTRING_LEN(str) - prefixlen); }
Like String#delete_prefix
, except that self
is modified in place. Returns self
if the prefix is removed, nil
otherwise.
static VALUE rb_str_delete_prefix_bang(VALUE str, VALUE prefix) { long prefixlen; str_modify_keep_cr(str); prefixlen = deleted_prefix_length(str, prefix); if (prefixlen <= 0) return Qnil; return rb_str_drop_bytes(str, prefixlen); }
Returns a copy of self
with trailing substring suffix
removed:
'hello'.delete_suffix('llo') # => "he" 'hello'.delete_suffix('hel') # => "hello" 'тест'.delete_suffix('ст') # => "те" 'こんにちは'.delete_suffix('ちは') # => "こんに"
Related: String#delete_suffix!
, String#delete_prefix
.
static VALUE rb_str_delete_suffix(VALUE str, VALUE suffix) { long suffixlen; suffixlen = deleted_suffix_length(str, suffix); if (suffixlen <= 0) return str_duplicate(rb_cString, str); return rb_str_subseq(str, 0, RSTRING_LEN(str) - suffixlen); }
Like String#delete_suffix
, except that self
is modified in place. Returns self
if the suffix is removed, nil
otherwise.
static VALUE rb_str_delete_suffix_bang(VALUE str, VALUE suffix) { long olen, suffixlen, len; str_modifiable(str); suffixlen = deleted_suffix_length(str, suffix); if (suffixlen <= 0) return Qnil; olen = RSTRING_LEN(str); str_modify_keep_cr(str); len = olen - suffixlen; STR_SET_LEN(str, len); TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str)); if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) { ENC_CODERANGE_CLEAR(str); } return str; }
Returns a string containing the downcased characters in self
:
s = 'Hello World!' # => "Hello World!" s.downcase # => "hello world!"
The casing may be affected by the given options
; see Case Mapping.
Related: String#downcase!
, String#upcase
, String#upcase!
.
static VALUE rb_str_downcase(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE; VALUE ret; flags = check_case_options(argc, argv, flags); enc = str_true_enc(str); if (case_option_single_p(flags, enc, str)) { ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str)); str_enc_copy_direct(ret, str); downcase_single(ret); } else if (flags&ONIGENC_CASE_ASCII_ONLY) { ret = rb_str_new(0, RSTRING_LEN(str)); rb_str_ascii_casemap(str, ret, &flags, enc); } else { ret = rb_str_casemap(str, &flags, enc); } return ret; }
Downcases the characters in self
; returns self
if any changes were made, nil
otherwise:
s = 'Hello World!' # => "Hello World!" s.downcase! # => "hello world!" s # => "hello world!" s.downcase! # => nil
The casing may be affected by the given options
; see Case Mapping.
Related: String#downcase
, String#upcase
, String#upcase!
.
static VALUE rb_str_downcase_bang(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE; flags = check_case_options(argc, argv, flags); str_modify_keep_cr(str); enc = str_true_enc(str); if (case_option_single_p(flags, enc, str)) { if (downcase_single(str)) flags |= ONIGENC_CASE_MODIFIED; } else if (flags&ONIGENC_CASE_ASCII_ONLY) rb_str_ascii_casemap(str, str, &flags, enc); else str_shared_replace(str, rb_str_casemap(str, &flags, enc)); if (ONIGENC_CASE_MODIFIED&flags) return str; return Qnil; }
Returns a printable version of self
, enclosed in double-quotes, with special characters escaped, and with non-printing characters replaced by hexadecimal notation:
"hello \n ''".dump # => "\"hello \\n ''\"" "\f\x00\xff\\\"".dump # => "\"\\f\\x00\\xFF\\\\\\\"\""
Related: String#undump
(inverse of String#dump
).
VALUE rb_str_dump(VALUE str) { int encidx = rb_enc_get_index(str); rb_encoding *enc = rb_enc_from_index(encidx); long len; const char *p, *pend; char *q, *qend; VALUE result; int u8 = (encidx == rb_utf8_encindex()); static const char nonascii_suffix[] = ".dup.force_encoding(\"%s\")"; len = 2; /* "" */ if (!rb_enc_asciicompat(enc)) { len += strlen(nonascii_suffix) - rb_strlen_lit("%s"); len += strlen(enc->name); } p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str); while (p < pend) { int clen; unsigned char c = *p++; switch (c) { case '"': case '\\': case '\n': case '\r': case '\t': case '\f': case '\013': case '\010': case '\007': case '\033': clen = 2; break; case '#': clen = IS_EVSTR(p, pend) ? 2 : 1; break; default: if (ISPRINT(c)) { clen = 1; } else { if (u8 && c > 0x7F) { /* \u notation */ int n = rb_enc_precise_mbclen(p-1, pend, enc); if (MBCLEN_CHARFOUND_P(n)) { unsigned int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc); if (cc <= 0xFFFF) clen = 6; /* \uXXXX */ else if (cc <= 0xFFFFF) clen = 9; /* \u{XXXXX} */ else clen = 10; /* \u{XXXXXX} */ p += MBCLEN_CHARFOUND_LEN(n)-1; break; } } clen = 4; /* \xNN */ } break; } if (clen > LONG_MAX - len) { rb_raise(rb_eRuntimeError, "string size too big"); } len += clen; } result = rb_str_new(0, len); p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str); q = RSTRING_PTR(result); qend = q + len + 1; *q++ = '"'; while (p < pend) { unsigned char c = *p++; if (c == '"' || c == '\\') { *q++ = '\\'; *q++ = c; } else if (c == '#') { if (IS_EVSTR(p, pend)) *q++ = '\\'; *q++ = '#'; } else if (c == '\n') { *q++ = '\\'; *q++ = 'n'; } else if (c == '\r') { *q++ = '\\'; *q++ = 'r'; } else if (c == '\t') { *q++ = '\\'; *q++ = 't'; } else if (c == '\f') { *q++ = '\\'; *q++ = 'f'; } else if (c == '\013') { *q++ = '\\'; *q++ = 'v'; } else if (c == '\010') { *q++ = '\\'; *q++ = 'b'; } else if (c == '\007') { *q++ = '\\'; *q++ = 'a'; } else if (c == '\033') { *q++ = '\\'; *q++ = 'e'; } else if (ISPRINT(c)) { *q++ = c; } else { *q++ = '\\'; if (u8) { int n = rb_enc_precise_mbclen(p-1, pend, enc) - 1; if (MBCLEN_CHARFOUND_P(n)) { int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc); p += n; if (cc <= 0xFFFF) snprintf(q, qend-q, "u%04X", cc); /* \uXXXX */ else snprintf(q, qend-q, "u{%X}", cc); /* \u{XXXXX} or \u{XXXXXX} */ q += strlen(q); continue; } } snprintf(q, qend-q, "x%02X", c); q += 3; } } *q++ = '"'; *q = '\0'; if (!rb_enc_asciicompat(enc)) { snprintf(q, qend-q, nonascii_suffix, enc->name); encidx = rb_ascii8bit_encindex(); } /* result from dump is ASCII */ rb_enc_associate_index(result, encidx); ENC_CODERANGE_SET(result, ENC_CODERANGE_7BIT); return result; }
Calls the given block with each successive byte from self
; returns self
:
'hello'.each_byte {|byte| print byte, ' ' } print "\n" 'тест'.each_byte {|byte| print byte, ' ' } print "\n" 'こんにちは'.each_byte {|byte| print byte, ' ' } print "\n"
Output:
104 101 108 108 111 209 130 208 181 209 129 209 130 227 129 147 227 130 147 227 129 171 227 129 161 227 129 175
Returns an enumerator if no block is given.
static VALUE rb_str_each_byte(VALUE str) { RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_byte_size); return rb_str_enumerate_bytes(str, 0); }
Calls the given block with each successive character from self
; returns self
:
'hello'.each_char {|char| print char, ' ' } print "\n" 'тест'.each_char {|char| print char, ' ' } print "\n" 'こんにちは'.each_char {|char| print char, ' ' } print "\n"
Output:
h e l l o т е с т こ ん に ち は
Returns an enumerator if no block is given.
static VALUE rb_str_each_char(VALUE str) { RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size); return rb_str_enumerate_chars(str, 0); }
Calls the given block with each successive codepoint from self
; each codepoint is the integer value for a character; returns self
:
'hello'.each_codepoint {|codepoint| print codepoint, ' ' } print "\n" 'тест'.each_codepoint {|codepoint| print codepoint, ' ' } print "\n" 'こんにちは'.each_codepoint {|codepoint| print codepoint, ' ' } print "\n"
Output:
104 101 108 108 111 1090 1077 1089 1090 12371 12435 12395 12385 12399
Returns an enumerator if no block is given.
static VALUE rb_str_each_codepoint(VALUE str) { RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size); return rb_str_enumerate_codepoints(str, 0); }
Calls the given block with each successive grapheme cluster from self
(see Unicode Grapheme Cluster Boundaries); returns self
:
s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈" s.each_grapheme_cluster {|gc| print gc, ' ' }
Output:
ä - p q r - b̈ - x y z - c̈
Returns an enumerator if no block is given.
static VALUE rb_str_each_grapheme_cluster(VALUE str) { RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_grapheme_cluster_size); return rb_str_enumerate_grapheme_clusters(str, 0); }
With a block given, forms the substrings (“lines”) that are the result of splitting self
at each occurrence of the given line separator line_sep
; passes each line to the block; returns self
:
s = <<~EOT This is the first line. This is line two. This is line four. This is line five. EOT s.each_line {|line| p line }
Output:
"This is the first line.\n" "This is line two.\n" "\n" "This is line four.\n" "This is line five.\n"
With a different line_sep
:
s.each_line(' is ') {|line| p line }
Output:
"This is " "the first line.\nThis is " "line two.\n\nThis is " "line four.\nThis is " "line five.\n"
With chomp
as true
, removes the trailing line_sep
from each line:
s.each_line(chomp: true) {|line| p line }
Output:
"This is the first line." "This is line two." "" "This is line four." "This is line five."
With an empty string as line_sep
, forms and passes “paragraphs” by splitting at each occurrence of two or more newlines:
s.each_line('') {|line| p line }
Output:
"This is the first line.\nThis is line two.\n\n" "This is line four.\nThis is line five.\n"
With no block given, returns an enumerator.
static VALUE rb_str_each_line(int argc, VALUE *argv, VALUE str) { RETURN_SIZED_ENUMERATOR(str, argc, argv, 0); return rb_str_enumerate_lines(argc, argv, str, 0); }
Returns true
if the length of self
is zero, false
otherwise:
"hello".empty? # => false " ".empty? # => false "".empty? # => true
static VALUE rb_str_empty(VALUE str) { return RBOOL(RSTRING_LEN(str) == 0); }
Returns a copy of self
transcoded as determined by dst_encoding
. By default, raises an exception if self
contains an invalid byte or a character not defined in dst_encoding
; that behavior may be modified by encoding options; see below.
With no arguments:
-
Uses the same encoding if
Encoding.default_internal
isnil
(the default):Encoding.default_internal # => nil s = "Ruby\x99".force_encoding('Windows-1252') s.encoding # => #<Encoding:Windows-1252> s.bytes # => [82, 117, 98, 121, 153] t = s.encode # => "Ruby\x99" t.encoding # => #<Encoding:Windows-1252> t.bytes # => [82, 117, 98, 121, 226, 132, 162]
-
Otherwise, uses the encoding
Encoding.default_internal
:Encoding.default_internal = 'UTF-8' t = s.encode # => "Ruby™" t.encoding # => #<Encoding:UTF-8>
With only argument dst_encoding
given, uses that encoding:
s = "Ruby\x99".force_encoding('Windows-1252') s.encoding # => #<Encoding:Windows-1252> t = s.encode('UTF-8') # => "Ruby™" t.encoding # => #<Encoding:UTF-8>
With arguments dst_encoding
and src_encoding
given, interprets self
using src_encoding
, encodes the new string using dst_encoding
:
s = "Ruby\x99" t = s.encode('UTF-8', 'Windows-1252') # => "Ruby™" t.encoding # => #<Encoding:UTF-8>
Optional keyword arguments enc_opts
specify encoding options; see Encoding Options.
Please note that, unless invalid: :replace
option is given, conversion from an encoding enc
to the same encoding enc
(independent of whether enc
is given explicitly or implicitly) is a no-op, i.e. the string is simply copied without any changes, and no exceptions are raised, even if there are invalid bytes.
static VALUE str_encode(int argc, VALUE *argv, VALUE str) { VALUE newstr = str; int encidx = str_transcode(argc, argv, &newstr); return encoded_dup(newstr, str, encidx); }
Like encode
, but applies encoding changes to self
; returns self
.
static VALUE str_encode_bang(int argc, VALUE *argv, VALUE str) { VALUE newstr; int encidx; rb_check_frozen(str); newstr = str; encidx = str_transcode(argc, argv, &newstr); if (encidx < 0) return str; if (newstr == str) { rb_enc_associate_index(str, encidx); return str; } rb_str_shared_replace(str, newstr); return str_encode_associate(str, encidx); }
Returns the Encoding
object that represents the encoding of obj.
VALUE rb_obj_encoding(VALUE obj) { int idx = rb_enc_get_index(obj); if (idx < 0) { rb_raise(rb_eTypeError, "unknown encoding"); } return rb_enc_from_encoding_index(idx & ENC_INDEX_MASK); }
Returns whether self
ends with any of the given strings
.
Returns true
if any given string matches the end, false
otherwise:
'hello'.end_with?('ello') #=> true 'hello'.end_with?('heaven', 'ello') #=> true 'hello'.end_with?('heaven', 'paradise') #=> false 'тест'.end_with?('т') # => true 'こんにちは'.end_with?('は') # => true
Related: String#start_with?
.
static VALUE rb_str_end_with(int argc, VALUE *argv, VALUE str) { int i; for (i=0; i<argc; i++) { VALUE tmp = argv[i]; const char *p, *s, *e; long slen, tlen; rb_encoding *enc; StringValue(tmp); enc = rb_enc_check(str, tmp); if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue; if ((slen = RSTRING_LEN(str)) < tlen) continue; p = RSTRING_PTR(str); e = p + slen; s = e - tlen; if (!at_char_boundary(p, s, e, enc)) continue; if (memcmp(s, RSTRING_PTR(tmp), tlen) == 0) return Qtrue; } return Qfalse; }
Returns true
if object
has the same length and content; as self
; false
otherwise:
s = 'foo' s.eql?('foo') # => true s.eql?('food') # => false s.eql?('FOO') # => false
Returns false
if the two strings’ encodings are not compatible:
"\u{e4 f6 fc}".encode("ISO-8859-1").eql?("\u{c4 d6 dc}") # => false
VALUE rb_str_eql(VALUE str1, VALUE str2) { if (str1 == str2) return Qtrue; if (!RB_TYPE_P(str2, T_STRING)) return Qfalse; return rb_str_eql_internal(str1, str2); }
Changes the encoding of self
to encoding
, which may be a string encoding name or an Encoding
object; returns self:
s = 'łał' s.bytes # => [197, 130, 97, 197, 130] s.encoding # => #<Encoding:UTF-8> s.force_encoding('ascii') # => "\xC5\x82a\xC5\x82" s.encoding # => #<Encoding:US-ASCII>
Does not change the underlying bytes:
s.bytes # => [197, 130, 97, 197, 130]
Makes the change even if the given encoding
is invalid for self
(as is the change above):
s.valid_encoding? # => false s.force_encoding(Encoding::UTF_8) # => "łał" s.valid_encoding? # => true
static VALUE rb_str_force_encoding(VALUE str, VALUE enc) { str_modifiable(str); rb_encoding *encoding = rb_to_encoding(enc); int idx = rb_enc_to_index(encoding); // If the encoding is unchanged, we do nothing. if (ENCODING_GET(str) == idx) { return str; } rb_enc_associate_index(str, idx); // If the coderange was 7bit and the new encoding is ASCII-compatible // we can keep the coderange. if (ENC_CODERANGE(str) == ENC_CODERANGE_7BIT && encoding && rb_enc_asciicompat(encoding)) { return str; } ENC_CODERANGE_CLEAR(str); return str; }
Returns the byte at zero-based index
as an integer, or nil
if index
is out of range:
s = 'abcde' # => "abcde" s.getbyte(0) # => 97 s.getbyte(-1) # => 101 s.getbyte(5) # => nil
Related: String#setbyte
.
VALUE rb_str_getbyte(VALUE str, VALUE index) { long pos = NUM2LONG(index); if (pos < 0) pos += RSTRING_LEN(str); if (pos < 0 || RSTRING_LEN(str) <= pos) return Qnil; return INT2FIX((unsigned char)RSTRING_PTR(str)[pos]); }
Returns an array of the grapheme clusters in self
(see Unicode Grapheme Cluster Boundaries):
s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈" s.grapheme_clusters # => ["ä", "-", "p", "q", "r", "-", "b̈", "-", "x", "y", "z", "-", "c̈"]
static VALUE rb_str_grapheme_clusters(VALUE str) { VALUE ary = WANTARRAY("grapheme_clusters", rb_str_strlen(str)); return rb_str_enumerate_grapheme_clusters(str, ary); }
Returns a copy of self
with all occurrences of the given pattern
replaced.
See Substitution Methods.
Returns an Enumerator
if no replacement
and no block given.
Related: String#sub
, String#sub!
, String#gsub!
.
static VALUE rb_str_gsub(int argc, VALUE *argv, VALUE str) { return str_gsub(argc, argv, str, 0); }
Performs the specified substring replacement(s) on self
; returns self
if any replacement occurred, nil
otherwise.
See Substitution Methods.
Returns an Enumerator
if no replacement
and no block given.
Related: String#sub
, String#gsub
, String#sub!
.
static VALUE rb_str_gsub_bang(int argc, VALUE *argv, VALUE str) { str_modify_keep_cr(str); return str_gsub(argc, argv, str, 1); }
Returns the integer hash value for self
. The value is based on the length, content and encoding of self
.
Related: Object#hash
.
static VALUE rb_str_hash_m(VALUE str) { st_index_t hval = rb_str_hash(str); return ST2FIX(hval); }
Interprets the leading substring of self
as a string of hexadecimal digits (with an optional sign and an optional 0x
) and returns the corresponding number; returns zero if there is no such leading substring:
'0x0a'.hex # => 10 '-1234'.hex # => -4660 '0'.hex # => 0 'non-numeric'.hex # => 0
Related: String#oct
.
static VALUE rb_str_hex(VALUE str) { return rb_str_to_inum(str, 16, FALSE); }
Returns true
if self
contains other_string
, false
otherwise:
s = 'foo' s.include?('f') # => true s.include?('fo') # => true s.include?('food') # => false
VALUE rb_str_include(VALUE str, VALUE arg) { long i; StringValue(arg); i = rb_str_index(str, arg, 0); return RBOOL(i != -1); }
Returns the integer index of the first match for the given argument, or nil
if none found; the search of self
is forward, and begins at position offset
(in characters).
With string argument substring
, returns the index of the first matching substring in self
:
'foo'.index('f') # => 0 'foo'.index('o') # => 1 'foo'.index('oo') # => 1 'foo'.index('ooo') # => nil 'тест'.index('с') # => 2 'こんにちは'.index('ち') # => 3
With Regexp
argument regexp
, returns the index of the first match in self
:
'foo'.index(/o./) # => 1 'foo'.index(/.o/) # => 0
With positive integer offset
, begins the search at position offset
:
'foo'.index('o', 1) # => 1 'foo'.index('o', 2) # => 2 'foo'.index('o', 3) # => nil 'тест'.index('с', 1) # => 2 'こんにちは'.index('ち', 2) # => 3
With negative integer offset
, selects the search position by counting backward from the end of self
:
'foo'.index('o', -1) # => 2 'foo'.index('o', -2) # => 1 'foo'.index('o', -3) # => 1 'foo'.index('o', -4) # => nil 'foo'.index(/o./, -2) # => 1 'foo'.index(/.o/, -2) # => 1
Related: String#rindex
.
static VALUE rb_str_index_m(int argc, VALUE *argv, VALUE str) { VALUE sub; VALUE initpos; rb_encoding *enc = STR_ENC_GET(str); long pos; if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) { long slen = str_strlen(str, enc); /* str's enc */ pos = NUM2LONG(initpos); if (pos < 0 ? (pos += slen) < 0 : pos > slen) { if (RB_TYPE_P(sub, T_REGEXP)) { rb_backref_set(Qnil); } return Qnil; } } else { pos = 0; } if (RB_TYPE_P(sub, T_REGEXP)) { pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos, enc, single_byte_optimizable(str)); if (rb_reg_search(sub, str, pos, 0) >= 0) { VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = rb_str_sublen(str, BEG(0)); return LONG2NUM(pos); } } else { StringValue(sub); pos = rb_str_index(str, sub, pos); if (pos >= 0) { pos = rb_str_sublen(str, pos); return LONG2NUM(pos); } } return Qnil; }
Replaces the contents of self
with the contents of other_string
:
s = 'foo' # => "foo" s.replace('bar') # => "bar"
VALUE rb_str_replace(VALUE str, VALUE str2) { str_modifiable(str); if (str == str2) return str; StringValue(str2); str_discard(str); return str_replace(str, str2); }
Inserts the given other_string
into self
; returns self
.
If the Integer
index
is positive, inserts other_string
at offset index
:
'foo'.insert(1, 'bar') # => "fbaroo"
If the Integer
index
is negative, counts backward from the end of self
and inserts other_string
at offset index+1
(that is, after self[index]
):
'foo'.insert(-2, 'bar') # => "fobaro"
static VALUE rb_str_insert(VALUE str, VALUE idx, VALUE str2) { long pos = NUM2LONG(idx); if (pos == -1) { return rb_str_append(str, str2); } else if (pos < 0) { pos++; } rb_str_update(str, pos, 0, str2); return str; }
Returns a printable version of self
, enclosed in double-quotes, and with special characters escaped:
s = "foo\tbar\tbaz\n" s.inspect # => "\"foo\\tbar\\tbaz\\n\""
VALUE rb_str_inspect(VALUE str) { int encidx = ENCODING_GET(str); rb_encoding *enc = rb_enc_from_index(encidx); const char *p, *pend, *prev; char buf[CHAR_ESC_LEN + 1]; VALUE result = rb_str_buf_new(0); rb_encoding *resenc = rb_default_internal_encoding(); int unicode_p = rb_enc_unicode_p(enc); int asciicompat = rb_enc_asciicompat(enc); if (resenc == NULL) resenc = rb_default_external_encoding(); if (!rb_enc_asciicompat(resenc)) resenc = rb_usascii_encoding(); rb_enc_associate(result, resenc); str_buf_cat2(result, "\""); p = RSTRING_PTR(str); pend = RSTRING_END(str); prev = p; while (p < pend) { unsigned int c, cc; int n; n = rb_enc_precise_mbclen(p, pend, enc); if (!MBCLEN_CHARFOUND_P(n)) { if (p > prev) str_buf_cat(result, prev, p - prev); n = rb_enc_mbminlen(enc); if (pend < p + n) n = (int)(pend - p); while (n--) { snprintf(buf, CHAR_ESC_LEN, "\\x%02X", *p & 0377); str_buf_cat(result, buf, strlen(buf)); prev = ++p; } continue; } n = MBCLEN_CHARFOUND_LEN(n); c = rb_enc_mbc_to_codepoint(p, pend, enc); p += n; if ((asciicompat || unicode_p) && (c == '"'|| c == '\\' || (c == '#' && p < pend && MBCLEN_CHARFOUND_P(rb_enc_precise_mbclen(p,pend,enc)) && (cc = rb_enc_codepoint(p,pend,enc), (cc == '$' || cc == '@' || cc == '{'))))) { if (p - n > prev) str_buf_cat(result, prev, p - n - prev); str_buf_cat2(result, "\\"); if (asciicompat || enc == resenc) { prev = p - n; continue; } } switch (c) { case '\n': cc = 'n'; break; case '\r': cc = 'r'; break; case '\t': cc = 't'; break; case '\f': cc = 'f'; break; case '\013': cc = 'v'; break; case '\010': cc = 'b'; break; case '\007': cc = 'a'; break; case 033: cc = 'e'; break; default: cc = 0; break; } if (cc) { if (p - n > prev) str_buf_cat(result, prev, p - n - prev); buf[0] = '\\'; buf[1] = (char)cc; str_buf_cat(result, buf, 2); prev = p; continue; } /* The special casing of 0x85 (NEXT_LINE) here is because * Oniguruma historically treats it as printable, but it * doesn't match the print POSIX bracket class or character * property in regexps. * * See Ruby Bug #16842 for details: * https://bugs.ruby-lang.org/issues/16842 */ if ((enc == resenc && rb_enc_isprint(c, enc) && c != 0x85) || (asciicompat && rb_enc_isascii(c, enc) && ISPRINT(c))) { continue; } else { if (p - n > prev) str_buf_cat(result, prev, p - n - prev); rb_str_buf_cat_escaped_char(result, c, unicode_p); prev = p; continue; } } if (p > prev) str_buf_cat(result, prev, p - prev); str_buf_cat2(result, "\""); return result; }
Returns the Symbol
corresponding to str, creating the symbol if it did not previously exist. See Symbol#id2name
.
"Koala".intern #=> :Koala s = 'cat'.to_sym #=> :cat s == :cat #=> true s = '@cat'.to_sym #=> :@cat s == :@cat #=> true
This can also be used to create symbols that cannot be represented using the :xxx
notation.
'cat and dog'.to_sym #=> :"cat and dog"
VALUE rb_str_intern(VALUE str) { VALUE sym; GLOBAL_SYMBOLS_ENTER(symbols); { sym = lookup_str_sym_with_lock(symbols, str); if (sym) { // ok } else if (USE_SYMBOL_GC) { rb_encoding *enc = rb_enc_get(str); rb_encoding *ascii = rb_usascii_encoding(); if (enc != ascii && sym_check_asciionly(str, false)) { str = rb_str_dup(str); rb_enc_associate(str, ascii); OBJ_FREEZE(str); enc = ascii; } else { str = rb_str_dup(str); OBJ_FREEZE(str); } str = rb_fstring(str); int type = rb_str_symname_type(str, IDSET_ATTRSET_FOR_INTERN); if (type < 0) type = ID_JUNK; sym = dsymbol_alloc(symbols, rb_cSymbol, str, enc, type); } else { ID id = intern_str(str, 0); sym = ID2SYM(id); } } GLOBAL_SYMBOLS_LEAVE(); return sym; }
Returns the count of characters (not bytes) in self
:
'foo'.length # => 3 'тест'.length # => 4 'こんにちは'.length # => 5
Contrast with String#bytesize
:
'foo'.bytesize # => 3 'тест'.bytesize # => 8 'こんにちは'.bytesize # => 15
VALUE rb_str_length(VALUE str) { return LONG2NUM(str_strlen(str, NULL)); }
Forms substrings (“lines”) of self
according to the given arguments (see String#each_line
for details); returns the lines in an array.
static VALUE rb_str_lines(int argc, VALUE *argv, VALUE str) { VALUE ary = WANTARRAY("lines", 0); return rb_str_enumerate_lines(argc, argv, str, ary); }
Returns a left-justified copy of self
.
If integer argument size
is greater than the size (in characters) of self
, returns a new string of length size
that is a copy of self
, left justified and padded on the right with pad_string
:
'hello'.ljust(10) # => "hello " ' hello'.ljust(10) # => " hello " 'hello'.ljust(10, 'ab') # => "helloababa" 'тест'.ljust(10) # => "тест " 'こんにちは'.ljust(10) # => "こんにちは "
If size
is not greater than the size of self
, returns a copy of self
:
'hello'.ljust(5) # => "hello" 'hello'.ljust(1) # => "hello"
Related: String#rjust
, String#center
.
static VALUE rb_str_ljust(int argc, VALUE *argv, VALUE str) { return rb_str_justify(argc, argv, str, 'l'); }
Returns a copy of self
with leading whitespace removed; see Whitespace in Strings:
whitespace = "\x00\t\n\v\f\r " s = whitespace + 'abc' + whitespace s # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r " s.lstrip # => "abc\u0000\t\n\v\f\r "
Related: String#rstrip
, String#strip
.
static VALUE rb_str_lstrip(VALUE str) { char *start; long len, loffset; RSTRING_GETMEM(str, start, len); loffset = lstrip_offset(str, start, start+len, STR_ENC_GET(str)); if (loffset <= 0) return str_duplicate(rb_cString, str); return rb_str_subseq(str, loffset, len - loffset); }
Like String#lstrip
, except that any modifications are made in self
; returns self
if any modification are made, nil
otherwise.
Related: String#rstrip!
, String#strip!
.
static VALUE rb_str_lstrip_bang(VALUE str) { rb_encoding *enc; char *start, *s; long olen, loffset; str_modify_keep_cr(str); enc = STR_ENC_GET(str); RSTRING_GETMEM(str, start, olen); loffset = lstrip_offset(str, start, start+olen, enc); if (loffset > 0) { long len = olen-loffset; s = start + loffset; memmove(start, s, len); STR_SET_LEN(str, len); TERM_FILL(start+len, rb_enc_mbminlen(enc)); return str; } return Qnil; }
Returns a MatchData
object (or nil
) based on self
and the given pattern
.
Note: also updates Global Variables at Regexp
.
-
Computes
regexp
by convertingpattern
(if not already aRegexp
).regexp = Regexp.new(pattern)
-
Computes
matchdata
, which will be either aMatchData
object ornil
(seeRegexp#match
):matchdata = <tt>regexp.match(self)
With no block given, returns the computed matchdata
:
'foo'.match('f') # => #<MatchData "f"> 'foo'.match('o') # => #<MatchData "o"> 'foo'.match('x') # => nil
If Integer
argument offset
is given, the search begins at index offset
:
'foo'.match('f', 1) # => nil 'foo'.match('o', 1) # => #<MatchData "o">
With a block given, calls the block with the computed matchdata
and returns the block’s return value:
'foo'.match(/o/) {|matchdata| matchdata } # => #<MatchData "o"> 'foo'.match(/x/) {|matchdata| matchdata } # => nil 'foo'.match(/f/, 1) {|matchdata| matchdata } # => nil
static VALUE rb_str_match_m(int argc, VALUE *argv, VALUE str) { VALUE re, result; if (argc < 1) rb_check_arity(argc, 1, 2); re = argv[0]; argv[0] = str; result = rb_funcallv(get_pat(re), rb_intern("match"), argc, argv); if (!NIL_P(result) && rb_block_given_p()) { return rb_yield(result); } return result; }
Returns true
or false
based on whether a match is found for self
and pattern
.
Note: does not update Global Variables at Regexp
.
Computes regexp
by converting pattern
(if not already a Regexp
).
regexp = Regexp.new(pattern)
Returns true
if self+.match(regexp)
returns a MatchData
object, false
otherwise:
'foo'.match?(/o/) # => true 'foo'.match?('o') # => true 'foo'.match?(/x/) # => false
If Integer
argument offset
is given, the search begins at index offset
:
'foo'.match?('f', 1) # => false 'foo'.match?('o', 1) # => true
static VALUE rb_str_match_m_p(int argc, VALUE *argv, VALUE str) { VALUE re; rb_check_arity(argc, 1, 2); re = get_pat(argv[0]); return rb_reg_match_p(re, str, argc > 1 ? NUM2LONG(argv[1]) : 0); }
Returns the successor to self
. The successor is calculated by incrementing characters.
The first character to be incremented is the rightmost alphanumeric: or, if no alphanumerics, the rightmost character:
'THX1138'.succ # => "THX1139" '<<koala>>'.succ # => "<<koalb>>" '***'.succ # => '**+'
The successor to a digit is another digit, “carrying” to the next-left character for a “rollover” from 9 to 0, and prepending another digit if necessary:
'00'.succ # => "01" '09'.succ # => "10" '99'.succ # => "100"
The successor to a letter is another letter of the same case, carrying to the next-left character for a rollover, and prepending another same-case letter if necessary:
'aa'.succ # => "ab" 'az'.succ # => "ba" 'zz'.succ # => "aaa" 'AA'.succ # => "AB" 'AZ'.succ # => "BA" 'ZZ'.succ # => "AAA"
The successor to a non-alphanumeric character is the next character in the underlying character set’s collating sequence, carrying to the next-left character for a rollover, and prepending another character if necessary:
s = 0.chr * 3 s # => "\x00\x00\x00" s.succ # => "\x00\x00\x01" s = 255.chr * 3 s # => "\xFF\xFF\xFF" s.succ # => "\x01\x00\x00\x00"
Carrying can occur between and among mixtures of alphanumeric characters:
s = 'zz99zz99' s.succ # => "aaa00aa00" s = '99zz99zz' s.succ # => "100aa00aa"
The successor to an empty String is a new empty String:
''.succ # => ""
Interprets the leading substring of self
as a string of octal digits (with an optional sign) and returns the corresponding number; returns zero if there is no such leading substring:
'123'.oct # => 83 '-377'.oct # => -255 '0377non-numeric'.oct # => 255 'non-numeric'.oct # => 0
If self
starts with 0
, radix indicators are honored; see Kernel#Integer
.
Related: String#hex
.
static VALUE rb_str_oct(VALUE str) { return rb_str_to_inum(str, -8, FALSE); }
Returns the integer ordinal of the first character of self
:
'h'.ord # => 104 'hello'.ord # => 104 'тест'.ord # => 1090 'こんにちは'.ord # => 12371
static VALUE rb_str_ord(VALUE s) { unsigned int c; c = rb_enc_codepoint(RSTRING_PTR(s), RSTRING_END(s), STR_ENC_GET(s)); return UINT2NUM(c); }
Returns a 3-element array of substrings of self
.
Matches a pattern against self
, scanning from the beginning. The pattern is:
-
string_or_regexp
itself, if it is aRegexp
. -
Regexp.quote(string_or_regexp)
, ifstring_or_regexp
is a string.
If the pattern is matched, returns pre-match, first-match, post-match:
'hello'.partition('l') # => ["he", "l", "lo"] 'hello'.partition('ll') # => ["he", "ll", "o"] 'hello'.partition('h') # => ["", "h", "ello"] 'hello'.partition('o') # => ["hell", "o", ""] 'hello'.partition(/l+/) #=> ["he", "ll", "o"] 'hello'.partition('') # => ["", "", "hello"] 'тест'.partition('т') # => ["", "т", "ест"] 'こんにちは'.partition('に') # => ["こん", "に", "ちは"]
If the pattern is not matched, returns a copy of self
and two empty strings:
'hello'.partition('x') # => ["hello", "", ""]
Related: String#rpartition
, String#split
.
static VALUE rb_str_partition(VALUE str, VALUE sep) { long pos; sep = get_pat_quoted(sep, 0); if (RB_TYPE_P(sep, T_REGEXP)) { if (rb_reg_search(sep, str, 0, 0) < 0) { goto failed; } VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = BEG(0); sep = rb_str_subseq(str, pos, END(0) - pos); } else { pos = rb_str_index(str, sep, 0); if (pos < 0) goto failed; } return rb_ary_new3(3, rb_str_subseq(str, 0, pos), sep, rb_str_subseq(str, pos+RSTRING_LEN(sep), RSTRING_LEN(str)-pos-RSTRING_LEN(sep))); failed: return rb_ary_new3(3, str_duplicate(rb_cString, str), str_new_empty_String(str), str_new_empty_String(str)); }
Prepends each string in other_strings
to self
and returns self
:
s = 'foo' s.prepend('bar', 'baz') # => "barbazfoo" s # => "barbazfoo"
Related: String#concat
.
static VALUE rb_str_prepend_multi(int argc, VALUE *argv, VALUE str) { str_modifiable(str); if (argc == 1) { rb_str_update(str, 0L, 0L, argv[0]); } else if (argc > 1) { int i; VALUE arg_str = rb_str_tmp_new(0); rb_enc_copy(arg_str, str); for (i = 0; i < argc; i++) { rb_str_append(arg_str, argv[i]); } rb_str_update(str, 0L, 0L, arg_str); } return str; }
Replaces the contents of self
with the contents of other_string
:
s = 'foo' # => "foo" s.replace('bar') # => "bar"
Returns a new string with the characters from self
in reverse order.
'stressed'.reverse # => "desserts"
static VALUE rb_str_reverse(VALUE str) { rb_encoding *enc; VALUE rev; char *s, *e, *p; int cr; if (RSTRING_LEN(str) <= 1) return str_duplicate(rb_cString, str); enc = STR_ENC_GET(str); rev = rb_str_new(0, RSTRING_LEN(str)); s = RSTRING_PTR(str); e = RSTRING_END(str); p = RSTRING_END(rev); cr = ENC_CODERANGE(str); if (RSTRING_LEN(str) > 1) { if (single_byte_optimizable(str)) { while (s < e) { *--p = *s++; } } else if (cr == ENC_CODERANGE_VALID) { while (s < e) { int clen = rb_enc_fast_mbclen(s, e, enc); p -= clen; memcpy(p, s, clen); s += clen; } } else { cr = rb_enc_asciicompat(enc) ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID; while (s < e) { int clen = rb_enc_mbclen(s, e, enc); if (clen > 1 || (*s & 0x80)) cr = ENC_CODERANGE_UNKNOWN; p -= clen; memcpy(p, s, clen); s += clen; } } } STR_SET_LEN(rev, RSTRING_LEN(str)); str_enc_copy_direct(rev, str); ENC_CODERANGE_SET(rev, cr); return rev; }
Returns self
with its characters reversed:
s = 'stressed' s.reverse! # => "desserts" s # => "desserts"
static VALUE rb_str_reverse_bang(VALUE str) { if (RSTRING_LEN(str) > 1) { if (single_byte_optimizable(str)) { char *s, *e, c; str_modify_keep_cr(str); s = RSTRING_PTR(str); e = RSTRING_END(str) - 1; while (s < e) { c = *s; *s++ = *e; *e-- = c; } } else { str_shared_replace(str, rb_str_reverse(str)); } } else { str_modify_keep_cr(str); } return str; }
Returns the Integer
index of the last occurrence of the given substring
, or nil
if none found:
'foo'.rindex('f') # => 0 'foo'.rindex('o') # => 2 'foo'.rindex('oo') # => 1 'foo'.rindex('ooo') # => nil
Returns the Integer
index of the last match for the given Regexp
regexp
, or nil
if none found:
'foo'.rindex(/f/) # => 0 'foo'.rindex(/o/) # => 2 'foo'.rindex(/oo/) # => 1 'foo'.rindex(/ooo/) # => nil
The last match means starting at the possible last position, not the last of longest matches.
'foo'.rindex(/o+/) # => 2 $~ #=> #<MatchData "o">
To get the last longest match, needs to combine with negative lookbehind.
'foo'.rindex(/(?<!o)o+/) # => 1 $~ #=> #<MatchData "oo">
Or String#index
with negative lookforward.
'foo'.index(/o+(?!.*o)/) # => 1 $~ #=> #<MatchData "oo">
Integer
argument offset
, if given and non-negative, specifies the maximum starting position in the
string to _end_ the search: 'foo'.rindex('o', 0) # => nil 'foo'.rindex('o', 1) # => 1 'foo'.rindex('o', 2) # => 2 'foo'.rindex('o', 3) # => 2
If offset
is a negative Integer
, the maximum starting position in the string to end the search is the sum of the string’s length and offset
:
'foo'.rindex('o', -1) # => 2 'foo'.rindex('o', -2) # => 1 'foo'.rindex('o', -3) # => nil 'foo'.rindex('o', -4) # => nil
Related: String#index
.
static VALUE rb_str_rindex_m(int argc, VALUE *argv, VALUE str) { VALUE sub; VALUE initpos; rb_encoding *enc = STR_ENC_GET(str); long pos, len = str_strlen(str, enc); /* str's enc */ if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) { pos = NUM2LONG(initpos); if (pos < 0 && (pos += len) < 0) { if (RB_TYPE_P(sub, T_REGEXP)) { rb_backref_set(Qnil); } return Qnil; } if (pos > len) pos = len; } else { pos = len; } if (RB_TYPE_P(sub, T_REGEXP)) { /* enc = rb_enc_check(str, sub); */ pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos, enc, single_byte_optimizable(str)); if (rb_reg_search(sub, str, pos, 1) >= 0) { VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = rb_str_sublen(str, BEG(0)); return LONG2NUM(pos); } } else { StringValue(sub); pos = rb_str_rindex(str, sub, pos); if (pos >= 0) { pos = rb_str_sublen(str, pos); return LONG2NUM(pos); } } return Qnil; }
Returns a right-justified copy of self
.
If integer argument size
is greater than the size (in characters) of self
, returns a new string of length size
that is a copy of self
, right justified and padded on the left with pad_string
:
'hello'.rjust(10) # => " hello" 'hello '.rjust(10) # => " hello " 'hello'.rjust(10, 'ab') # => "ababahello" 'тест'.rjust(10) # => " тест" 'こんにちは'.rjust(10) # => " こんにちは"
If size
is not greater than the size of self
, returns a copy of self
:
'hello'.rjust(5, 'ab') # => "hello" 'hello'.rjust(1, 'ab') # => "hello"
Related: String#ljust
, String#center
.
static VALUE rb_str_rjust(int argc, VALUE *argv, VALUE str) { return rb_str_justify(argc, argv, str, 'r'); }
Returns a 3-element array of substrings of self
.
Matches a pattern against self
, scanning backwards from the end. The pattern is:
-
string_or_regexp
itself, if it is aRegexp
. -
Regexp.quote(string_or_regexp)
, ifstring_or_regexp
is a string.
If the pattern is matched, returns pre-match, last-match, post-match:
'hello'.rpartition('l') # => ["hel", "l", "o"] 'hello'.rpartition('ll') # => ["he", "ll", "o"] 'hello'.rpartition('h') # => ["", "h", "ello"] 'hello'.rpartition('o') # => ["hell", "o", ""] 'hello'.rpartition(/l+/) # => ["hel", "l", "o"] 'hello'.rpartition('') # => ["hello", "", ""] 'тест'.rpartition('т') # => ["тес", "т", ""] 'こんにちは'.rpartition('に') # => ["こん", "に", "ちは"]
If the pattern is not matched, returns two empty strings and a copy of self
:
'hello'.rpartition('x') # => ["", "", "hello"]
Related: String#partition
, String#split
.
static VALUE rb_str_rpartition(VALUE str, VALUE sep) { long pos = RSTRING_LEN(str); sep = get_pat_quoted(sep, 0); if (RB_TYPE_P(sep, T_REGEXP)) { if (rb_reg_search(sep, str, pos, 1) < 0) { goto failed; } VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); pos = BEG(0); sep = rb_str_subseq(str, pos, END(0) - pos); } else { pos = rb_str_sublen(str, pos); pos = rb_str_rindex(str, sep, pos); if (pos < 0) { goto failed; } } return rb_ary_new3(3, rb_str_subseq(str, 0, pos), sep, rb_str_subseq(str, pos+RSTRING_LEN(sep), RSTRING_LEN(str)-pos-RSTRING_LEN(sep))); failed: return rb_ary_new3(3, str_new_empty_String(str), str_new_empty_String(str), str_duplicate(rb_cString, str)); }
Returns a copy of the receiver with trailing whitespace removed; see Whitespace in Strings:
whitespace = "\x00\t\n\v\f\r " s = whitespace + 'abc' + whitespace s # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r " s.rstrip # => "\u0000\t\n\v\f\r abc"
Related: String#lstrip
, String#strip
.
static VALUE rb_str_rstrip(VALUE str) { rb_encoding *enc; char *start; long olen, roffset; enc = STR_ENC_GET(str); RSTRING_GETMEM(str, start, olen); roffset = rstrip_offset(str, start, start+olen, enc); if (roffset <= 0) return str_duplicate(rb_cString, str); return rb_str_subseq(str, 0, olen-roffset); }
Like String#rstrip
, except that any modifications are made in self
; returns self
if any modification are made, nil
otherwise.
Related: String#lstrip!
, String#strip!
.
static VALUE rb_str_rstrip_bang(VALUE str) { rb_encoding *enc; char *start; long olen, roffset; str_modify_keep_cr(str); enc = STR_ENC_GET(str); RSTRING_GETMEM(str, start, olen); roffset = rstrip_offset(str, start, start+olen, enc); if (roffset > 0) { long len = olen - roffset; STR_SET_LEN(str, len); TERM_FILL(start+len, rb_enc_mbminlen(enc)); return str; } return Qnil; }
Matches a pattern against self
; the pattern is:
-
string_or_regexp
itself, if it is aRegexp
. -
Regexp.quote(string_or_regexp)
, ifstring_or_regexp
is a string.
Iterates through self
, generating a collection of matching results:
-
If the pattern contains no groups, each result is the matched string,
$&
. -
If the pattern contains groups, each result is an array containing one entry per group.
With no block given, returns an array of the results:
s = 'cruel world' s.scan(/\w+/) # => ["cruel", "world"] s.scan(/.../) # => ["cru", "el ", "wor"] s.scan(/(...)/) # => [["cru"], ["el "], ["wor"]] s.scan(/(..)(..)/) # => [["cr", "ue"], ["l ", "wo"]]
With a block given, calls the block with each result; returns self
:
s.scan(/\w+/) {|w| print "<<#{w}>> " } print "\n" s.scan(/(.)(.)/) {|x,y| print y, x } print "\n"
Output:
<<cruel>> <<world>> rceu lowlr
static VALUE rb_str_scan(VALUE str, VALUE pat) { VALUE result; long start = 0; long last = -1, prev = 0; char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str); pat = get_pat_quoted(pat, 1); mustnot_broken(str); if (!rb_block_given_p()) { VALUE ary = rb_ary_new(); while (!NIL_P(result = scan_once(str, pat, &start, 0))) { last = prev; prev = start; rb_ary_push(ary, result); } if (last >= 0) rb_pat_search(pat, str, last, 1); else rb_backref_set(Qnil); return ary; } while (!NIL_P(result = scan_once(str, pat, &start, 1))) { last = prev; prev = start; rb_yield(result); str_mod_check(str, p, len); } if (last >= 0) rb_pat_search(pat, str, last, 1); return str; }
Returns a copy of self
with each invalid byte sequence replaced by the given replacement_string
.
With no block given and no argument, replaces each invalid sequence with the default replacement string ("�"
for a Unicode encoding, '?'
otherwise):
s = "foo\x81\x81bar" s.scrub # => "foo��bar"
With no block given and argument replacement_string
given, replaces each invalid sequence with that string:
"foo\x81\x81bar".scrub('xyzzy') # => "fooxyzzyxyzzybar"
With a block given, replaces each invalid sequence with the value of the block:
"foo\x81\x81bar".scrub {|bytes| p bytes; 'XYZZY' } # => "fooXYZZYXYZZYbar"
Output:
"\x81" "\x81"
static VALUE str_scrub(int argc, VALUE *argv, VALUE str) { VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil; VALUE new = rb_str_scrub(str, repl); return NIL_P(new) ? str_duplicate(rb_cString, str): new; }
Like String#scrub
, except that any replacements are made in self
.
static VALUE str_scrub_bang(int argc, VALUE *argv, VALUE str) { VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil; VALUE new = rb_str_scrub(str, repl); if (!NIL_P(new)) rb_str_replace(str, new); return str; }
Sets the byte at zero-based index
to integer
; returns integer
:
s = 'abcde' # => "abcde" s.setbyte(0, 98) # => 98 s # => "bbcde"
Related: String#getbyte
.
static VALUE rb_str_setbyte(VALUE str, VALUE index, VALUE value) { long pos = NUM2LONG(index); long len = RSTRING_LEN(str); char *ptr, *head, *left = 0; rb_encoding *enc; int cr = ENC_CODERANGE_UNKNOWN, width, nlen; if (pos < -len || len <= pos) rb_raise(rb_eIndexError, "index %ld out of string", pos); if (pos < 0) pos += len; VALUE v = rb_to_int(value); VALUE w = rb_int_and(v, INT2FIX(0xff)); char byte = (char)(NUM2INT(w) & 0xFF); if (!str_independent(str)) str_make_independent(str); enc = STR_ENC_GET(str); head = RSTRING_PTR(str); ptr = &head[pos]; if (!STR_EMBED_P(str)) { cr = ENC_CODERANGE(str); switch (cr) { case ENC_CODERANGE_7BIT: left = ptr; *ptr = byte; if (ISASCII(byte)) goto end; nlen = rb_enc_precise_mbclen(left, head+len, enc); if (!MBCLEN_CHARFOUND_P(nlen)) ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN); else ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID); goto end; case ENC_CODERANGE_VALID: left = rb_enc_left_char_head(head, ptr, head+len, enc); width = rb_enc_precise_mbclen(left, head+len, enc); *ptr = byte; nlen = rb_enc_precise_mbclen(left, head+len, enc); if (!MBCLEN_CHARFOUND_P(nlen)) ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN); else if (MBCLEN_CHARFOUND_LEN(nlen) != width || ISASCII(byte)) ENC_CODERANGE_CLEAR(str); goto end; } } ENC_CODERANGE_CLEAR(str); *ptr = byte; end: return value; }
Returns the count of characters (not bytes) in self
:
'foo'.length # => 3 'тест'.length # => 4 'こんにちは'.length # => 5
Contrast with String#bytesize
:
'foo'.bytesize # => 3 'тест'.bytesize # => 8 'こんにちは'.bytesize # => 15
Returns the substring of self
specified by the arguments. See examples at String Slices.
Removes and returns the substring of self
specified by the arguments. See String Slices.
A few examples:
string = "This is a string" string.slice!(2) #=> "i" string.slice!(3..6) #=> " is " string.slice!(/s.*t/) #=> "sa st" string.slice!("r") #=> "r" string #=> "Thing"
static VALUE rb_str_slice_bang(int argc, VALUE *argv, VALUE str) { VALUE result = Qnil; VALUE indx; long beg, len = 1; char *p; rb_check_arity(argc, 1, 2); str_modify_keep_cr(str); indx = argv[0]; if (RB_TYPE_P(indx, T_REGEXP)) { if (rb_reg_search(indx, str, 0, 0) < 0) return Qnil; VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); int nth = 0; if (argc > 1 && (nth = rb_reg_backref_number(match, argv[1])) < 0) { if ((nth += regs->num_regs) <= 0) return Qnil; } else if (nth >= regs->num_regs) return Qnil; beg = BEG(nth); len = END(nth) - beg; goto subseq; } else if (argc == 2) { beg = NUM2LONG(indx); len = NUM2LONG(argv[1]); goto num_index; } else if (FIXNUM_P(indx)) { beg = FIX2LONG(indx); if (!(p = rb_str_subpos(str, beg, &len))) return Qnil; if (!len) return Qnil; beg = p - RSTRING_PTR(str); goto subseq; } else if (RB_TYPE_P(indx, T_STRING)) { beg = rb_str_index(str, indx, 0); if (beg == -1) return Qnil; len = RSTRING_LEN(indx); result = str_duplicate(rb_cString, indx); goto squash; } else { switch (rb_range_beg_len(indx, &beg, &len, str_strlen(str, NULL), 0)) { case Qnil: return Qnil; case Qfalse: beg = NUM2LONG(indx); if (!(p = rb_str_subpos(str, beg, &len))) return Qnil; if (!len) return Qnil; beg = p - RSTRING_PTR(str); goto subseq; default: goto num_index; } } num_index: if (!(p = rb_str_subpos(str, beg, &len))) return Qnil; beg = p - RSTRING_PTR(str); subseq: result = rb_str_new(RSTRING_PTR(str)+beg, len); rb_enc_cr_str_copy_for_substr(result, str); squash: if (len > 0) { if (beg == 0) { rb_str_drop_bytes(str, len); } else { char *sptr = RSTRING_PTR(str); long slen = RSTRING_LEN(str); if (beg + len > slen) /* pathological check */ len = slen - beg; memmove(sptr + beg, sptr + beg + len, slen - (beg + len)); slen -= len; STR_SET_LEN(str, slen); TERM_FILL(&sptr[slen], TERM_LEN(str)); } } return result; }
Returns an array of substrings of self
that are the result of splitting self
at each occurrence of the given field separator field_sep
.
When field_sep
is $;
:
-
If
$;
isnil
(its default value), the split occurs just as iffield_sep
were given as a space character (see below). -
If
$;
is a string, the split ocurs just as iffield_sep
were given as that string (see below).
When field_sep
is ' '
and limit
is nil
, the split occurs at each sequence of whitespace:
'abc def ghi'.split(' ') => ["abc", "def", "ghi"] "abc \n\tdef\t\n ghi".split(' ') # => ["abc", "def", "ghi"] 'abc def ghi'.split(' ') => ["abc", "def", "ghi"] ''.split(' ') => []
When field_sep
is a string different from ' '
and limit
is nil
, the split occurs at each occurrence of field_sep
; trailing empty substrings are not returned:
'abracadabra'.split('ab') => ["", "racad", "ra"] 'aaabcdaaa'.split('a') => ["", "", "", "bcd"] ''.split('a') => [] '3.14159'.split('1') => ["3.", "4", "59"] '!@#$%^$&*($)_+'.split('$') # => ["!@#", "%^", "&*(", ")_+"] 'тест'.split('т') => ["", "ес"] 'こんにちは'.split('に') => ["こん", "ちは"]
When field_sep
is a Regexp
and limit
is nil
, the split occurs at each occurrence of a match; trailing empty substrings are not returned:
'abracadabra'.split(/ab/) # => ["", "racad", "ra"] 'aaabcdaaa'.split(/a/) => ["", "", "", "bcd"] 'aaabcdaaa'.split(//) => ["a", "a", "a", "b", "c", "d", "a", "a", "a"] '1 + 1 == 2'.split(/\W+/) # => ["1", "1", "2"]
If the Regexp contains groups, their matches are also included in the returned array:
'1:2:3'.split(/(:)()()/, 2) # => ["1", ":", "", "", "2:3"]
As seen above, if limit
is nil
, trailing empty substrings are not returned; the same is true if limit
is zero:
'aaabcdaaa'.split('a') => ["", "", "", "bcd"] 'aaabcdaaa'.split('a', 0) # => ["", "", "", "bcd"]
If limit
is positive integer n
, no more than n - 1-
splits occur, so that at most n
substrings are returned, and trailing empty substrings are included:
'aaabcdaaa'.split('a', 1) # => ["aaabcdaaa"] 'aaabcdaaa'.split('a', 2) # => ["", "aabcdaaa"] 'aaabcdaaa'.split('a', 5) # => ["", "", "", "bcd", "aa"] 'aaabcdaaa'.split('a', 7) # => ["", "", "", "bcd", "", "", ""] 'aaabcdaaa'.split('a', 8) # => ["", "", "", "bcd", "", "", ""]
Note that if field_sep
is a Regexp containing groups, their matches are in the returned array, but do not count toward the limit.
If limit
is negative, it behaves the same as if limit
was nil
, meaning that there is no limit, and trailing empty substrings are included:
'aaabcdaaa'.split('a', -1) # => ["", "", "", "bcd", "", "", ""]
If a block is given, it is called with each substring:
'abc def ghi'.split(' ') {|substring| p substring }
Output:
"abc" "def" "ghi"
Related: String#partition
, String#rpartition
.
static VALUE rb_str_split_m(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; VALUE spat; VALUE limit; split_type_t split_type; long beg, end, i = 0, empty_count = -1; int lim = 0; VALUE result, tmp; result = rb_block_given_p() ? Qfalse : Qnil; if (rb_scan_args(argc, argv, "02", &spat, &limit) == 2) { lim = NUM2INT(limit); if (lim <= 0) limit = Qnil; else if (lim == 1) { if (RSTRING_LEN(str) == 0) return result ? rb_ary_new2(0) : str; tmp = str_duplicate(rb_cString, str); if (!result) { rb_yield(tmp); return str; } return rb_ary_new3(1, tmp); } i = 1; } if (NIL_P(limit) && !lim) empty_count = 0; enc = STR_ENC_GET(str); split_type = SPLIT_TYPE_REGEXP; if (!NIL_P(spat)) { spat = get_pat_quoted(spat, 0); } else if (NIL_P(spat = rb_fs)) { split_type = SPLIT_TYPE_AWK; } else if (!(spat = rb_fs_check(spat))) { rb_raise(rb_eTypeError, "value of $; must be String or Regexp"); } else { rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$; is set to non-nil value"); } if (split_type != SPLIT_TYPE_AWK) { switch (BUILTIN_TYPE(spat)) { case T_REGEXP: rb_reg_options(spat); /* check if uninitialized */ tmp = RREGEXP_SRC(spat); split_type = literal_split_pattern(tmp, SPLIT_TYPE_REGEXP); if (split_type == SPLIT_TYPE_AWK) { spat = tmp; split_type = SPLIT_TYPE_STRING; } break; case T_STRING: mustnot_broken(spat); split_type = literal_split_pattern(spat, SPLIT_TYPE_STRING); break; default: UNREACHABLE_RETURN(Qnil); } } #define SPLIT_STR(beg, len) (empty_count = split_string(result, str, beg, len, empty_count)) beg = 0; char *ptr = RSTRING_PTR(str); char *eptr = RSTRING_END(str); if (split_type == SPLIT_TYPE_AWK) { char *bptr = ptr; int skip = 1; unsigned int c; if (result) result = rb_ary_new(); end = beg; if (is_ascii_string(str)) { while (ptr < eptr) { c = (unsigned char)*ptr++; if (skip) { if (ascii_isspace(c)) { beg = ptr - bptr; } else { end = ptr - bptr; skip = 0; if (!NIL_P(limit) && lim <= i) break; } } else if (ascii_isspace(c)) { SPLIT_STR(beg, end-beg); skip = 1; beg = ptr - bptr; if (!NIL_P(limit)) ++i; } else { end = ptr - bptr; } } } else { while (ptr < eptr) { int n; c = rb_enc_codepoint_len(ptr, eptr, &n, enc); ptr += n; if (skip) { if (rb_isspace(c)) { beg = ptr - bptr; } else { end = ptr - bptr; skip = 0; if (!NIL_P(limit) && lim <= i) break; } } else if (rb_isspace(c)) { SPLIT_STR(beg, end-beg); skip = 1; beg = ptr - bptr; if (!NIL_P(limit)) ++i; } else { end = ptr - bptr; } } } } else if (split_type == SPLIT_TYPE_STRING) { char *str_start = ptr; char *substr_start = ptr; char *sptr = RSTRING_PTR(spat); long slen = RSTRING_LEN(spat); if (result) result = rb_ary_new(); mustnot_broken(str); enc = rb_enc_check(str, spat); while (ptr < eptr && (end = rb_memsearch(sptr, slen, ptr, eptr - ptr, enc)) >= 0) { /* Check we are at the start of a char */ char *t = rb_enc_right_char_head(ptr, ptr + end, eptr, enc); if (t != ptr + end) { ptr = t; continue; } SPLIT_STR(substr_start - str_start, (ptr+end) - substr_start); ptr += end + slen; substr_start = ptr; if (!NIL_P(limit) && lim <= ++i) break; } beg = ptr - str_start; } else if (split_type == SPLIT_TYPE_CHARS) { char *str_start = ptr; int n; if (result) result = rb_ary_new_capa(RSTRING_LEN(str)); mustnot_broken(str); enc = rb_enc_get(str); while (ptr < eptr && (n = rb_enc_precise_mbclen(ptr, eptr, enc)) > 0) { SPLIT_STR(ptr - str_start, n); ptr += n; if (!NIL_P(limit) && lim <= ++i) break; } beg = ptr - str_start; } else { if (result) result = rb_ary_new(); long len = RSTRING_LEN(str); long start = beg; long idx; int last_null = 0; struct re_registers *regs; VALUE match = 0; for (; rb_reg_search(spat, str, start, 0) >= 0; (match ? (rb_match_unbusy(match), rb_backref_set(match)) : (void)0)) { match = rb_backref_get(); if (!result) rb_match_busy(match); regs = RMATCH_REGS(match); end = BEG(0); if (start == end && BEG(0) == END(0)) { if (!ptr) { SPLIT_STR(0, 0); break; } else if (last_null == 1) { SPLIT_STR(beg, rb_enc_fast_mbclen(ptr+beg, eptr, enc)); beg = start; } else { if (start == len) start++; else start += rb_enc_fast_mbclen(ptr+start,eptr,enc); last_null = 1; continue; } } else { SPLIT_STR(beg, end-beg); beg = start = END(0); } last_null = 0; for (idx=1; idx < regs->num_regs; idx++) { if (BEG(idx) == -1) continue; SPLIT_STR(BEG(idx), END(idx)-BEG(idx)); } if (!NIL_P(limit) && lim <= ++i) break; } if (match) rb_match_unbusy(match); } if (RSTRING_LEN(str) > 0 && (!NIL_P(limit) || RSTRING_LEN(str) > beg || lim < 0)) { SPLIT_STR(beg, RSTRING_LEN(str)-beg); } return result ? result : str; }
Returns a copy of self
with characters specified by selectors
“squeezed” (see Multiple Character Selectors):
“Squeezed” means that each multiple-character run of a selected character is squeezed down to a single character; with no arguments given, squeezes all characters:
"yellow moon".squeeze #=> "yelow mon" " now is the".squeeze(" ") #=> " now is the" "putters shoot balls".squeeze("m-z") #=> "puters shot balls"
static VALUE rb_str_squeeze(int argc, VALUE *argv, VALUE str) { str = str_duplicate(rb_cString, str); rb_str_squeeze_bang(argc, argv, str); return str; }
Like String#squeeze
, but modifies self
in place. Returns self
if any changes were made, nil
otherwise.
static VALUE rb_str_squeeze_bang(int argc, VALUE *argv, VALUE str) { char squeez[TR_TABLE_SIZE]; rb_encoding *enc = 0; VALUE del = 0, nodel = 0; unsigned char *s, *send, *t; int i, modify = 0; int ascompat, singlebyte = single_byte_optimizable(str); unsigned int save; if (argc == 0) { enc = STR_ENC_GET(str); } else { for (i=0; i<argc; i++) { VALUE s = argv[i]; StringValue(s); enc = rb_enc_check(str, s); if (singlebyte && !single_byte_optimizable(s)) singlebyte = 0; tr_setup_table(s, squeez, i==0, &del, &nodel, enc); } } str_modify_keep_cr(str); s = t = (unsigned char *)RSTRING_PTR(str); if (!s || RSTRING_LEN(str) == 0) return Qnil; send = (unsigned char *)RSTRING_END(str); save = -1; ascompat = rb_enc_asciicompat(enc); if (singlebyte) { while (s < send) { unsigned int c = *s++; if (c != save || (argc > 0 && !squeez[c])) { *t++ = save = c; } } } else { while (s < send) { unsigned int c; int clen; if (ascompat && (c = *s) < 0x80) { if (c != save || (argc > 0 && !squeez[c])) { *t++ = save = c; } s++; } else { c = rb_enc_codepoint_len((char *)s, (char *)send, &clen, enc); if (c != save || (argc > 0 && !tr_find(c, squeez, del, nodel))) { if (t != s) rb_enc_mbcput(c, t, enc); save = c; t += clen; } s += clen; } } } TERM_FILL((char *)t, TERM_LEN(str)); if ((char *)t - RSTRING_PTR(str) != RSTRING_LEN(str)) { STR_SET_LEN(str, (char *)t - RSTRING_PTR(str)); modify = 1; } if (modify) return str; return Qnil; }
Returns whether self
starts with any of the given string_or_regexp
.
Matches patterns against the beginning of self
. For each given string_or_regexp
, the pattern is:
-
string_or_regexp
itself, if it is aRegexp
. -
Regexp.quote(string_or_regexp)
, ifstring_or_regexp
is a string.
Returns true
if any pattern matches the beginning, false
otherwise:
'hello'.start_with?('hell') # => true 'hello'.start_with?(/H/i) # => true 'hello'.start_with?('heaven', 'hell') # => true 'hello'.start_with?('heaven', 'paradise') # => false 'тест'.start_with?('т') # => true 'こんにちは'.start_with?('こ') # => true
Related: String#end_with?
.
static VALUE rb_str_start_with(int argc, VALUE *argv, VALUE str) { int i; for (i=0; i<argc; i++) { VALUE tmp = argv[i]; if (RB_TYPE_P(tmp, T_REGEXP)) { if (rb_reg_start_with_p(tmp, str)) return Qtrue; } else { const char *p, *s, *e; long slen, tlen; rb_encoding *enc; StringValue(tmp); enc = rb_enc_check(str, tmp); if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue; if ((slen = RSTRING_LEN(str)) < tlen) continue; p = RSTRING_PTR(str); e = p + slen; s = p + tlen; if (!at_char_right_boundary(p, s, e, enc)) continue; if (memcmp(p, RSTRING_PTR(tmp), tlen) == 0) return Qtrue; } } return Qfalse; }
Returns a copy of the receiver with leading and trailing whitespace removed; see Whitespace in Strings:
whitespace = "\x00\t\n\v\f\r " s = whitespace + 'abc' + whitespace s # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r " s.strip # => "abc"
Related: String#lstrip
, String#rstrip
.
static VALUE rb_str_strip(VALUE str) { char *start; long olen, loffset, roffset; rb_encoding *enc = STR_ENC_GET(str); RSTRING_GETMEM(str, start, olen); loffset = lstrip_offset(str, start, start+olen, enc); roffset = rstrip_offset(str, start+loffset, start+olen, enc); if (loffset <= 0 && roffset <= 0) return str_duplicate(rb_cString, str); return rb_str_subseq(str, loffset, olen-loffset-roffset); }
Like String#strip
, except that any modifications are made in self
; returns self
if any modification are made, nil
otherwise.
Related: String#lstrip!
, String#strip!
.
static VALUE rb_str_strip_bang(VALUE str) { char *start; long olen, loffset, roffset; rb_encoding *enc; str_modify_keep_cr(str); enc = STR_ENC_GET(str); RSTRING_GETMEM(str, start, olen); loffset = lstrip_offset(str, start, start+olen, enc); roffset = rstrip_offset(str, start+loffset, start+olen, enc); if (loffset > 0 || roffset > 0) { long len = olen-roffset; if (loffset > 0) { len -= loffset; memmove(start, start + loffset, len); } STR_SET_LEN(str, len); TERM_FILL(start+len, rb_enc_mbminlen(enc)); return str; } return Qnil; }
Returns a copy of self
with only the first occurrence (not all occurrences) of the given pattern
replaced.
See Substitution Methods.
Related: String#sub!
, String#gsub
, String#gsub!
.
static VALUE rb_str_sub(int argc, VALUE *argv, VALUE str) { str = str_duplicate(rb_cString, str); rb_str_sub_bang(argc, argv, str); return str; }
Returns self
with only the first occurrence (not all occurrences) of the given pattern
replaced.
See Substitution Methods.
Related: String#sub
, String#gsub
, String#gsub!
.
static VALUE rb_str_sub_bang(int argc, VALUE *argv, VALUE str) { VALUE pat, repl, hash = Qnil; int iter = 0; long plen; int min_arity = rb_block_given_p() ? 1 : 2; long beg; rb_check_arity(argc, min_arity, 2); if (argc == 1) { iter = 1; } else { repl = argv[1]; hash = rb_check_hash_type(argv[1]); if (NIL_P(hash)) { StringValue(repl); } } pat = get_pat_quoted(argv[0], 1); str_modifiable(str); beg = rb_pat_search(pat, str, 0, 1); if (beg >= 0) { rb_encoding *enc; int cr = ENC_CODERANGE(str); long beg0, end0; VALUE match, match0 = Qnil; struct re_registers *regs; char *p, *rp; long len, rlen; match = rb_backref_get(); regs = RMATCH_REGS(match); if (RB_TYPE_P(pat, T_STRING)) { beg0 = beg; end0 = beg0 + RSTRING_LEN(pat); match0 = pat; } else { beg0 = BEG(0); end0 = END(0); if (iter) match0 = rb_reg_nth_match(0, match); } if (iter || !NIL_P(hash)) { p = RSTRING_PTR(str); len = RSTRING_LEN(str); if (iter) { repl = rb_obj_as_string(rb_yield(match0)); } else { repl = rb_hash_aref(hash, rb_str_subseq(str, beg0, end0 - beg0)); repl = rb_obj_as_string(repl); } str_mod_check(str, p, len); rb_check_frozen(str); } else { repl = rb_reg_regsub(repl, str, regs, RB_TYPE_P(pat, T_STRING) ? Qnil : pat); } enc = rb_enc_compatible(str, repl); if (!enc) { rb_encoding *str_enc = STR_ENC_GET(str); p = RSTRING_PTR(str); len = RSTRING_LEN(str); if (coderange_scan(p, beg0, str_enc) != ENC_CODERANGE_7BIT || coderange_scan(p+end0, len-end0, str_enc) != ENC_CODERANGE_7BIT) { rb_raise(rb_eEncCompatError, "incompatible character encodings: %s and %s", rb_enc_name(str_enc), rb_enc_name(STR_ENC_GET(repl))); } enc = STR_ENC_GET(repl); } rb_str_modify(str); rb_enc_associate(str, enc); if (ENC_CODERANGE_UNKNOWN < cr && cr < ENC_CODERANGE_BROKEN) { int cr2 = ENC_CODERANGE(repl); if (cr2 == ENC_CODERANGE_BROKEN || (cr == ENC_CODERANGE_VALID && cr2 == ENC_CODERANGE_7BIT)) cr = ENC_CODERANGE_UNKNOWN; else cr = cr2; } plen = end0 - beg0; rlen = RSTRING_LEN(repl); len = RSTRING_LEN(str); if (rlen > plen) { RESIZE_CAPA(str, len + rlen - plen); } p = RSTRING_PTR(str); if (rlen != plen) { memmove(p + beg0 + rlen, p + beg0 + plen, len - beg0 - plen); } rp = RSTRING_PTR(repl); memmove(p + beg0, rp, rlen); len += rlen - plen; STR_SET_LEN(str, len); TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str)); ENC_CODERANGE_SET(str, cr); RB_GC_GUARD(match); return str; } return Qnil; }
Returns the successor to self
. The successor is calculated by incrementing characters.
The first character to be incremented is the rightmost alphanumeric: or, if no alphanumerics, the rightmost character:
'THX1138'.succ # => "THX1139" '<<koala>>'.succ # => "<<koalb>>" '***'.succ # => '**+'
The successor to a digit is another digit, “carrying” to the next-left character for a “rollover” from 9 to 0, and prepending another digit if necessary:
'00'.succ # => "01" '09'.succ # => "10" '99'.succ # => "100"
The successor to a letter is another letter of the same case, carrying to the next-left character for a rollover, and prepending another same-case letter if necessary:
'aa'.succ # => "ab" 'az'.succ # => "ba" 'zz'.succ # => "aaa" 'AA'.succ # => "AB" 'AZ'.succ # => "BA" 'ZZ'.succ # => "AAA"
The successor to a non-alphanumeric character is the next character in the underlying character set’s collating sequence, carrying to the next-left character for a rollover, and prepending another character if necessary:
s = 0.chr * 3 s # => "\x00\x00\x00" s.succ # => "\x00\x00\x01" s = 255.chr * 3 s # => "\xFF\xFF\xFF" s.succ # => "\x01\x00\x00\x00"
Carrying can occur between and among mixtures of alphanumeric characters:
s = 'zz99zz99' s.succ # => "aaa00aa00" s = '99zz99zz' s.succ # => "100aa00aa"
The successor to an empty String is a new empty String:
''.succ # => ""
VALUE rb_str_succ(VALUE orig) { VALUE str; str = rb_str_new(RSTRING_PTR(orig), RSTRING_LEN(orig)); rb_enc_cr_str_copy_for_substr(str, orig); return str_succ(str); }
Equivalent to String#succ
, but modifies self
in place; returns self
.
static VALUE rb_str_succ_bang(VALUE str) { rb_str_modify(str); str_succ(str); return str; }
Returns a basic n
-bit checksum of the characters in self
; the checksum is the sum of the binary value of each byte in self
, modulo 2**n - 1
:
'hello'.sum # => 532 'hello'.sum(4) # => 4 'hello'.sum(64) # => 532 'тест'.sum # => 1405 'こんにちは'.sum # => 2582
This is not a particularly strong checksum.
static VALUE rb_str_sum(int argc, VALUE *argv, VALUE str) { int bits = 16; char *ptr, *p, *pend; long len; VALUE sum = INT2FIX(0); unsigned long sum0 = 0; if (rb_check_arity(argc, 0, 1) && (bits = NUM2INT(argv[0])) < 0) { bits = 0; } ptr = p = RSTRING_PTR(str); len = RSTRING_LEN(str); pend = p + len; while (p < pend) { if (FIXNUM_MAX - UCHAR_MAX < sum0) { sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0)); str_mod_check(str, ptr, len); sum0 = 0; } sum0 += (unsigned char)*p; p++; } if (bits == 0) { if (sum0) { sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0)); } } else { if (sum == INT2FIX(0)) { if (bits < (int)sizeof(long)*CHAR_BIT) { sum0 &= (((unsigned long)1)<<bits)-1; } sum = LONG2FIX(sum0); } else { VALUE mod; if (sum0) { sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0)); } mod = rb_funcall(INT2FIX(1), idLTLT, 1, INT2FIX(bits)); mod = rb_funcall(mod, '-', 1, INT2FIX(1)); sum = rb_funcall(sum, '&', 1, mod); } } return sum; }
Returns a string containing the characters in self
, with cases reversed; each uppercase character is downcased; each lowercase character is upcased:
s = 'Hello World!' # => "Hello World!" s.swapcase # => "hELLO wORLD!"
The casing may be affected by the given options
; see Case Mapping.
Related: String#swapcase!
.
static VALUE rb_str_swapcase(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE; VALUE ret; flags = check_case_options(argc, argv, flags); enc = str_true_enc(str); if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str_duplicate(rb_cString, str); if (flags&ONIGENC_CASE_ASCII_ONLY) { ret = rb_str_new(0, RSTRING_LEN(str)); rb_str_ascii_casemap(str, ret, &flags, enc); } else { ret = rb_str_casemap(str, &flags, enc); } return ret; }
Upcases each lowercase character in self
; downcases uppercase character; returns self
if any changes were made, nil
otherwise:
s = 'Hello World!' # => "Hello World!" s.swapcase! # => "hELLO wORLD!" s # => "hELLO wORLD!" ''.swapcase! # => nil
The casing may be affected by the given options
; see Case Mapping.
Related: String#swapcase
.
static VALUE rb_str_swapcase_bang(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE; flags = check_case_options(argc, argv, flags); str_modify_keep_cr(str); enc = str_true_enc(str); if (flags&ONIGENC_CASE_ASCII_ONLY) rb_str_ascii_casemap(str, str, &flags, enc); else str_shared_replace(str, rb_str_casemap(str, &flags, enc)); if (ONIGENC_CASE_MODIFIED&flags) return str; return Qnil; }
Returns self
interpreted as a Complex
object; leading whitespace and trailing garbage are ignored:
'9'.to_c # => (9+0i) '2.5'.to_c # => (2.5+0i) '2.5/1'.to_c # => ((5/2)+0i) '-3/2'.to_c # => ((-3/2)+0i) '-i'.to_c # => (0-1i) '45i'.to_c # => (0+45i) '3-4i'.to_c # => (3-4i) '-4e2-4e-2i'.to_c # => (-400.0-0.04i) '-0.0-0.0i'.to_c # => (-0.0-0.0i) '1/2+3/4i'.to_c # => ((1/2)+(3/4)*i) '1.0@0'.to_c # => (1+0.0i) "1.0@#{Math::PI/2}".to_c # => (0.0+1i) "1.0@#{Math::PI}".to_c # => (-1+0.0i)
Returns Complex zero if the string cannot be converted:
'ruby'.to_c # => (0+0i)
See Kernel#Complex
.
static VALUE string_to_c(VALUE self) { VALUE num; rb_must_asciicompat(self); (void)parse_comp(rb_str_fill_terminator(self, 1), FALSE, &num); return num; }
Returns the result of interpreting leading characters in self
as a Float:
'3.14159'.to_f # => 3.14159 '1.234e-2'.to_f # => 0.01234
Characters past a leading valid number (in the given base
) are ignored:
'3.14 (pi to two places)'.to_f # => 3.14
Returns zero if there is no leading valid number:
'abcdef'.to_f # => 0.0
static VALUE rb_str_to_f(VALUE str) { return DBL2NUM(rb_str_to_dbl(str, FALSE)); }
Returns the result of interpreting leading characters in self
as an integer in the given base
(which must be in (0, 2..36)):
'123456'.to_i # => 123456 '123def'.to_i(16) # => 1195503
With base
zero, string object
may contain leading characters to specify the actual base:
'123def'.to_i(0) # => 123 '0123def'.to_i(0) # => 83 '0b123def'.to_i(0) # => 1 '0o123def'.to_i(0) # => 83 '0d123def'.to_i(0) # => 123 '0x123def'.to_i(0) # => 1195503
Characters past a leading valid number (in the given base
) are ignored:
'12.345'.to_i # => 12 '12345'.to_i(2) # => 1
Returns zero if there is no leading valid number:
'abcdef'.to_i # => 0 '2'.to_i(2) # => 0
static VALUE rb_str_to_i(int argc, VALUE *argv, VALUE str) { int base = 10; if (rb_check_arity(argc, 0, 1) && (base = NUM2INT(argv[0])) < 0) { rb_raise(rb_eArgError, "invalid radix %d", base); } return rb_str_to_inum(str, base, FALSE); }
Returns the result of interpreting leading characters in str
as a rational. Leading whitespace and extraneous characters past the end of a valid number are ignored. Digit sequences can be separated by an underscore. If there is not a valid number at the start of str
, zero is returned. This method never raises an exception.
' 2 '.to_r #=> (2/1) '300/2'.to_r #=> (150/1) '-9.2'.to_r #=> (-46/5) '-9.2e2'.to_r #=> (-920/1) '1_234_567'.to_r #=> (1234567/1) '21 June 09'.to_r #=> (21/1) '21/06/09'.to_r #=> (7/2) 'BWV 1079'.to_r #=> (0/1)
NOTE: “0.3”.to_r isn’t the same as 0.3.to_r. The former is equivalent to “3/10”.to_r, but the latter isn’t so.
"0.3".to_r == 3/10r #=> true 0.3.to_r == 3/10r #=> false
See also Kernel#Rational
.
static VALUE string_to_r(VALUE self) { VALUE num; rb_must_asciicompat(self); num = parse_rat(RSTRING_PTR(self), RSTRING_END(self), 0, TRUE); if (RB_FLOAT_TYPE_P(num) && !FLOAT_ZERO_P(num)) rb_raise(rb_eFloatDomainError, "Infinity"); return num; }
Returns self
if self
is a String, or self
converted to a String if self
is a subclass of String.
static VALUE rb_str_to_s(VALUE str) { if (rb_obj_class(str) != rb_cString) { return str_duplicate(rb_cString, str); } return str; }
Returns self
if self
is a String, or self
converted to a String if self
is a subclass of String.
Returns the Symbol
corresponding to str, creating the symbol if it did not previously exist. See Symbol#id2name
.
"Koala".intern #=> :Koala s = 'cat'.to_sym #=> :cat s == :cat #=> true s = '@cat'.to_sym #=> :@cat s == :@cat #=> true
This can also be used to create symbols that cannot be represented using the :xxx
notation.
'cat and dog'.to_sym #=> :"cat and dog"
Returns a copy of self
with each character specified by string selector
translated to the corresponding character in string replacements
. The correspondence is positional:
-
Each occurrence of the first character specified by
selector
is translated to the first character inreplacements
. -
Each occurrence of the second character specified by
selector
is translated to the second character inreplacements
. -
And so on.
Example:
'hello'.tr('el', 'ip') #=> "hippo"
If replacements
is shorter than selector
, it is implicitly padded with its own last character:
'hello'.tr('aeiou', '-') # => "h-ll-" 'hello'.tr('aeiou', 'AA-') # => "hAll-"
Arguments selector
and replacements
must be valid character selectors (see Character Selectors), and may use any of its valid forms, including negation, ranges, and escaping:
# Negation. 'hello'.tr('^aeiou', '-') # => "-e--o" # Ranges. 'ibm'.tr('b-z', 'a-z') # => "hal" # Escapes. 'hel^lo'.tr('\^aeiou', '-') # => "h-l-l-" # Escaped leading caret. 'i-b-m'.tr('b\-z', 'a-z') # => "ibabm" # Escaped embedded hyphen. 'foo\\bar'.tr('ab\\', 'XYZ') # => "fooZYXr" # Escaped backslash.
static VALUE rb_str_tr(VALUE str, VALUE src, VALUE repl) { str = str_duplicate(rb_cString, str); tr_trans(str, src, repl, 0); return str; }
Like String#tr
, but modifies self
in place. Returns self
if any changes were made, nil
otherwise.
static VALUE rb_str_tr_bang(VALUE str, VALUE src, VALUE repl) { return tr_trans(str, src, repl, 0); }
Like String#tr
, but also squeezes the modified portions of the translated string; returns a new string (translated and squeezed).
'hello'.tr_s('l', 'r') #=> "hero" 'hello'.tr_s('el', '-') #=> "h-o" 'hello'.tr_s('el', 'hx') #=> "hhxo"
Related: String#squeeze
.
static VALUE rb_str_tr_s(VALUE str, VALUE src, VALUE repl) { str = str_duplicate(rb_cString, str); tr_trans(str, src, repl, 1); return str; }
Like String#tr_s
, but modifies self
in place. Returns self
if any changes were made, nil
otherwise.
Related: String#squeeze!
.
static VALUE rb_str_tr_s_bang(VALUE str, VALUE src, VALUE repl) { return tr_trans(str, src, repl, 1); }
Returns an unescaped version of self
:
s_orig = "\f\x00\xff\\\"" # => "\f\u0000\xFF\\\"" s_dumped = s_orig.dump # => "\"\\f\\x00\\xFF\\\\\\\"\"" s_undumped = s_dumped.undump # => "\f\u0000\xFF\\\"" s_undumped == s_orig # => true
Related: String#dump
(inverse of String#undump
).
static VALUE str_undump(VALUE str) { const char *s = RSTRING_PTR(str); const char *s_end = RSTRING_END(str); rb_encoding *enc = rb_enc_get(str); VALUE undumped = rb_enc_str_new(s, 0L, enc); bool utf8 = false; bool binary = false; int w; rb_must_asciicompat(str); if (rb_str_is_ascii_only_p(str) == Qfalse) { rb_raise(rb_eRuntimeError, "non-ASCII character detected"); } if (!str_null_check(str, &w)) { rb_raise(rb_eRuntimeError, "string contains null byte"); } if (RSTRING_LEN(str) < 2) goto invalid_format; if (*s != '"') goto invalid_format; /* strip '"' at the start */ s++; for (;;) { if (s >= s_end) { rb_raise(rb_eRuntimeError, "unterminated dumped string"); } if (*s == '"') { /* epilogue */ s++; if (s == s_end) { /* ascii compatible dumped string */ break; } else { static const char force_encoding_suffix[] = ".force_encoding(\""; /* "\")" */ static const char dup_suffix[] = ".dup"; const char *encname; int encidx; ptrdiff_t size; /* check separately for strings dumped by older versions */ size = sizeof(dup_suffix) - 1; if (s_end - s > size && memcmp(s, dup_suffix, size) == 0) s += size; size = sizeof(force_encoding_suffix) - 1; if (s_end - s <= size) goto invalid_format; if (memcmp(s, force_encoding_suffix, size) != 0) goto invalid_format; s += size; if (utf8) { rb_raise(rb_eRuntimeError, "dumped string contained Unicode escape but used force_encoding"); } encname = s; s = memchr(s, '"', s_end-s); size = s - encname; if (!s) goto invalid_format; if (s_end - s != 2) goto invalid_format; if (s[0] != '"' || s[1] != ')') goto invalid_format; encidx = rb_enc_find_index2(encname, (long)size); if (encidx < 0) { rb_raise(rb_eRuntimeError, "dumped string has unknown encoding name"); } rb_enc_associate_index(undumped, encidx); } break; } if (*s == '\\') { s++; if (s >= s_end) { rb_raise(rb_eRuntimeError, "invalid escape"); } undump_after_backslash(undumped, &s, s_end, &enc, &utf8, &binary); } else { rb_str_cat(undumped, s++, 1); } } RB_GC_GUARD(str); return undumped; invalid_format: rb_raise(rb_eRuntimeError, "invalid dumped string; not wrapped with '\"' nor '\"...\".force_encoding(\"...\")' form"); }
Returns a copy of self
with Unicode normalization applied.
Argument form
must be one of the following symbols (see Unicode normalization forms):
-
:nfc
: Canonical decomposition, followed by canonical composition. -
:nfd
: Canonical decomposition. -
:nfkc
: Compatibility decomposition, followed by canonical composition. -
:nfkd
: Compatibility decomposition.
The encoding of self
must be one of:
-
Encoding::UTF_8
-
Encoding::UTF_16BE
-
Encoding::UTF_16LE
-
Encoding::UTF_32BE
-
Encoding::UTF_32LE
-
Encoding::GB18030
-
Encoding::UCS_2BE
-
Encoding::UCS_4BE
Examples:
"a\u0300".unicode_normalize # => "a" "\u00E0".unicode_normalize(:nfd) # => "a "
Related: String#unicode_normalize!
, String#unicode_normalized?
.
static VALUE rb_str_unicode_normalize(int argc, VALUE *argv, VALUE str) { return unicode_normalize_common(argc, argv, str, id_normalize); }
Like String#unicode_normalize
, except that the normalization is performed on self
.
Related String#unicode_normalized?
.
static VALUE rb_str_unicode_normalize_bang(int argc, VALUE *argv, VALUE str) { return rb_str_replace(str, unicode_normalize_common(argc, argv, str, id_normalize)); }
Returns true
if self
is in the given form
of Unicode normalization, false
otherwise. The form
must be one of :nfc
, :nfd
, :nfkc
, or :nfkd
.
Examples:
"a\u0300".unicode_normalized? # => false "a\u0300".unicode_normalized?(:nfd) # => true "\u00E0".unicode_normalized? # => true "\u00E0".unicode_normalized?(:nfd) # => false
Raises an exception if self
is not in a Unicode encoding:
s = "\xE0".force_encoding('ISO-8859-1') s.unicode_normalized? # Raises Encoding::CompatibilityError.
Related: String#unicode_normalize
, String#unicode_normalize!
.
static VALUE rb_str_unicode_normalized_p(int argc, VALUE *argv, VALUE str) { return unicode_normalize_common(argc, argv, str, id_normalized_p); }
Extracts data from self
, forming objects that become the elements of a new array; returns that array. See Packed Data.
# File ruby_3_3_3/pack.rb, line 19 def unpack(fmt, offset: 0) Primitive.pack_unpack(fmt, offset) end
Like String#unpack
, but unpacks and returns only the first extracted object. See Packed Data.
# File ruby_3_3_3/pack.rb, line 28 def unpack1(fmt, offset: 0) Primitive.pack_unpack1(fmt, offset) end
Returns a string containing the upcased characters in self
:
s = 'Hello World!' # => "Hello World!" s.upcase # => "HELLO WORLD!"
The casing may be affected by the given options
; see Case Mapping.
Related: String#upcase!
, String#downcase
, String#downcase!
.
static VALUE rb_str_upcase(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE; VALUE ret; flags = check_case_options(argc, argv, flags); enc = str_true_enc(str); if (case_option_single_p(flags, enc, str)) { ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str)); str_enc_copy_direct(ret, str); upcase_single(ret); } else if (flags&ONIGENC_CASE_ASCII_ONLY) { ret = rb_str_new(0, RSTRING_LEN(str)); rb_str_ascii_casemap(str, ret, &flags, enc); } else { ret = rb_str_casemap(str, &flags, enc); } return ret; }
Upcases the characters in self
; returns self
if any changes were made, nil
otherwise:
s = 'Hello World!' # => "Hello World!" s.upcase! # => "HELLO WORLD!" s # => "HELLO WORLD!" s.upcase! # => nil
The casing may be affected by the given options
; see Case Mapping.
Related: String#upcase
, String#downcase
, String#downcase!
.
static VALUE rb_str_upcase_bang(int argc, VALUE *argv, VALUE str) { rb_encoding *enc; OnigCaseFoldType flags = ONIGENC_CASE_UPCASE; flags = check_case_options(argc, argv, flags); str_modify_keep_cr(str); enc = str_true_enc(str); if (case_option_single_p(flags, enc, str)) { if (upcase_single(str)) flags |= ONIGENC_CASE_MODIFIED; } else if (flags&ONIGENC_CASE_ASCII_ONLY) rb_str_ascii_casemap(str, str, &flags, enc); else str_shared_replace(str, rb_str_casemap(str, &flags, enc)); if (ONIGENC_CASE_MODIFIED&flags) return str; return Qnil; }
With a block given, calls the block with each String value returned by successive calls to String#succ
; the first value is self
, the next is self.succ
, and so on; the sequence terminates when value other_string
is reached; returns self
:
'a8'.upto('b6') {|s| print s, ' ' } # => "a8"
Output:
a8 a9 b0 b1 b2 b3 b4 b5 b6
If argument exclusive
is given as a truthy object, the last value is omitted:
'a8'.upto('b6', true) {|s| print s, ' ' } # => "a8"
Output:
a8 a9 b0 b1 b2 b3 b4 b5
If other_string
would not be reached, does not call the block:
'25'.upto('5') {|s| fail s } 'aa'.upto('a') {|s| fail s }
With no block given, returns a new Enumerator:
'a8'.upto('b6') # => #<Enumerator: "a8":upto("b6")>
static VALUE rb_str_upto(int argc, VALUE *argv, VALUE beg) { VALUE end, exclusive; rb_scan_args(argc, argv, "11", &end, &exclusive); RETURN_ENUMERATOR(beg, argc, argv); return rb_str_upto_each(beg, end, RTEST(exclusive), str_upto_i, Qnil); }
Returns true
if self
is encoded correctly, false
otherwise:
"\xc2\xa1".force_encoding("UTF-8").valid_encoding? # => true "\xc2".force_encoding("UTF-8").valid_encoding? # => false "\x80".force_encoding("UTF-8").valid_encoding? # => false
static VALUE rb_str_valid_encoding_p(VALUE str) { int cr = rb_enc_str_coderange(str); return RBOOL(cr != ENC_CODERANGE_BROKEN); }