In Files

  • array.c
  • pack.c

Array

Arrays are ordered, integer-indexed collections of any object. Array indexing starts at 0, as in C or Java. A negative index is assumed to be relative to the end of the array—that is, an index of -1 indicates the last element of the array, -2 is the next to last element in the array, and so on.

Public Class Methods

[](*args) click to toggle source

Returns a new array populated with the given objects.

Array.[]( 1, 'a', /^A/ )
Array[ 1, 'a', /^A/ ]
[ 1, 'a', /^A/ ]
 
               static VALUE
rb_ary_s_create(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    VALUE ary = ary_alloc(klass);

    if (argc > 0) {
        RARRAY(ary)->ptr = ALLOC_N(VALUE, argc);
        MEMCPY(RARRAY(ary)->ptr, argv, VALUE, argc);
    }
    RARRAY(ary)->len = RARRAY(ary)->aux.capa = argc;

    return ary;
}
            
new(size=0, obj=nil) click to toggle source
new(array)
new(size) {|index| block }

Returns a new array. In the first form, the new array is empty. In the second it is created with size copies of obj (that is, size references to the same obj). The third form creates a copy of the array passed as a parameter (the array is generated by calling #to_ary on the parameter). In the last form, an array of the given size is created. Each element in this array is calculated by passing the element’s index to the given block and storing the return value.

Array.new
Array.new(2)
Array.new(5, "A")

# only one copy of the object is created
a = Array.new(2, Hash.new)
a[0]['cat'] = 'feline'
a
a[1]['cat'] = 'Felix'
a

# here multiple copies are created
a = Array.new(2) { Hash.new }
a[0]['cat'] = 'feline'
a

squares = Array.new(5) {|i| i*i}
squares

copy = Array.new(squares)
 
               static VALUE
rb_ary_initialize(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long len;
    VALUE size, val;

    rb_ary_modify(ary);
    if (rb_scan_args(argc, argv, "02", &size, &val) == 0) {
        RARRAY(ary)->len = 0;
        if (rb_block_given_p()) {
            rb_warning("given block not used");
        }
        return ary;
    }

    if (argc == 1 && !FIXNUM_P(size)) {
        val = rb_check_array_type(size);
        if (!NIL_P(val)) {
            rb_ary_replace(ary, val);
            return ary;
        }
    }

    len = NUM2LONG(size);
    if (len < 0) {
        rb_raise(rb_eArgError, "negative array size");
    }
    if (len > ARY_MAX_SIZE) {
        rb_raise(rb_eArgError, "array size too big");
    }
    if (len > RARRAY(ary)->aux.capa) {
        REALLOC_N(RARRAY(ary)->ptr, VALUE, len);
        RARRAY(ary)->aux.capa = len;
    }
    if (rb_block_given_p()) {
        long i;

        if (argc == 2) {
            rb_warn("block supersedes default value argument");
        }
        for (i=0; i<len; i++) {
            rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
            RARRAY(ary)->len = i + 1;
        }
    }
    else {
        memfill(RARRAY(ary)->ptr, len, val);
        RARRAY(ary)->len = len;
    }

    return ary;
}
            

Public Instance Methods

array & other_array click to toggle source

Set Intersection—Returns a new array containing elements common to the two arrays, with no duplicates.

[ 1, 1, 3, 5 ] & [ 1, 2, 3 ]   #=> [ 1, 3 ]
 
               static VALUE
rb_ary_and(ary1, ary2)
    VALUE ary1, ary2;
{
    VALUE hash, ary3, v, vv;
    long i;

    ary2 = to_ary(ary2);
    ary3 = rb_ary_new2(RARRAY(ary1)->len < RARRAY(ary2)->len ?
            RARRAY(ary1)->len : RARRAY(ary2)->len);
    hash = ary_make_hash(ary2, 0);

    for (i=0; i<RARRAY(ary1)->len; i++) {
        v = vv = rb_ary_elt(ary1, i);
        if (st_delete(RHASH(hash)->tbl, (st_data_t*)&vv, 0)) {
            rb_ary_push(ary3, v);
        }
    }

    return ary3;
}
            
array * int → an_array click to toggle source
array * str → a_string

Repetition—With a String argument, equivalent to self.join(str). Otherwise, returns a new array built by concatenating the int copies of self.

[ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
[ 1, 2, 3 ] * ","  #=> "1,2,3"
 
               static VALUE
rb_ary_times(ary, times)
    VALUE ary, times;
{
    VALUE ary2, tmp;
    long i, len;

    tmp = rb_check_string_type(times);
    if (!NIL_P(tmp)) {
        return rb_ary_join(ary, tmp);
    }

    len = NUM2LONG(times);
    if (len == 0) return ary_new(rb_obj_class(ary), 0);
    if (len < 0) {
        rb_raise(rb_eArgError, "negative argument");
    }
    if (ARY_MAX_SIZE/len < RARRAY(ary)->len) {
        rb_raise(rb_eArgError, "argument too big");
    }
    len *= RARRAY(ary)->len;

    ary2 = ary_new(rb_obj_class(ary), len);
    RARRAY(ary2)->len = len;

    for (i=0; i<len; i+=RARRAY(ary)->len) {
        MEMCPY(RARRAY(ary2)->ptr+i, RARRAY(ary)->ptr, VALUE, RARRAY(ary)->len);
    }
    OBJ_INFECT(ary2, ary);

    return ary2;
}
            
array + other_array → an_array click to toggle source

Concatenation—Returns a new array built by concatenating the two arrays together to produce a third array.

[ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
 
               VALUE
rb_ary_plus(x, y)
    VALUE x, y;
{
    VALUE z;
    long len;

    y = to_ary(y);
    len = RARRAY(x)->len + RARRAY(y)->len;
    z = rb_ary_new2(len);
    MEMCPY(RARRAY(z)->ptr, RARRAY(x)->ptr, VALUE, RARRAY(x)->len);
    MEMCPY(RARRAY(z)->ptr + RARRAY(x)->len, RARRAY(y)->ptr, VALUE, RARRAY(y)->len);
    RARRAY(z)->len = len;
    return z;
}
            
array - other_array → an_array click to toggle source

Array Difference---Returns a new array that is a copy of the original array, removing any items that also appear in other_array. (If you need set-like behavior, see the library class Set.)

[ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]
 
               static VALUE
rb_ary_diff(ary1, ary2)
    VALUE ary1, ary2;
{
    VALUE ary3;
    volatile VALUE hash;
    long i;

    hash = ary_make_hash(to_ary(ary2), 0);
    ary3 = rb_ary_new();

    for (i=0; i<RARRAY(ary1)->len; i++) {
        if (st_lookup(RHASH(hash)->tbl, RARRAY(ary1)->ptr[i], 0)) continue;
        rb_ary_push(ary3, rb_ary_elt(ary1, i));
    }
    return ary3;
}
            
array << obj → array click to toggle source

Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.

[ 1, 2 ] << "c" << "d" << [ 3, 4 ]
        #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]
 
               VALUE
rb_ary_push(ary, item)
    VALUE ary;
    VALUE item;
{
    rb_ary_store(ary, RARRAY(ary)->len, item);
    return ary;
}
            
array <=> other_array → -1, 0, +1 click to toggle source

Comparison—Returns an integer (-1, 0, or +1) if this array is less than, equal to, or greater than other_array. Each object in each array is compared (using <=>). If any value isn’t equal, then that inequality is the return value. If all the values found are equal, then the return is based on a comparison of the array lengths. Thus, two arrays are “equal” according to Array#<=> if and only if they have the same length and the value of each element is equal to the value of the corresponding element in the other array.

[ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
[ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
 
               VALUE
rb_ary_cmp(ary1, ary2)
    VALUE ary1, ary2;
{
    long len;
    VALUE v;

    ary2 = to_ary(ary2);
    if (ary1 == ary2) return INT2FIX(0);
    v = rb_exec_recursive(recursive_cmp, ary1, ary2);
    if (v != Qundef) return v;
    len = RARRAY(ary1)->len - RARRAY(ary2)->len;
    if (len == 0) return INT2FIX(0);
    if (len > 0) return INT2FIX(1);
    return INT2FIX(-1);
}
            
array == other_array → bool click to toggle source

Equality—Two arrays are equal if they contain the same number of elements and if each element is equal to (according to Object.==) the corresponding element in the other array.

[ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
[ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
[ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false
 
               static VALUE
rb_ary_equal(ary1, ary2)
    VALUE ary1, ary2;
{
    if (ary1 == ary2) return Qtrue;
    if (TYPE(ary2) != T_ARRAY) {
        if (!rb_respond_to(ary2, rb_intern("to_ary"))) {
            return Qfalse;
        }
        return rb_equal(ary2, ary1);
    }
    if (RARRAY(ary1)->len != RARRAY(ary2)->len) return Qfalse;
    return rb_exec_recursive(recursive_equal, ary1, ary2);
}
            
array[index] → obj or nil click to toggle source
array[start, length] → an_array or nil
array[range] → an_array or nil
slice(index) → obj or nil
slice(start, length) → an_array or nil
slice(range) → an_array or nil

Element Reference—Returns the element at index, or returns a subarray starting at start and continuing for length elements, or returns a subarray specified by range. Negative indices count backward from the end of the array (-1 is the last element). Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []
 
               VALUE
rb_ary_aref(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
        if (SYMBOL_P(argv[0])) {
            rb_raise(rb_eTypeError, "Symbol as array index");
        }
        beg = NUM2LONG(argv[0]);
        len = NUM2LONG(argv[1]);
        if (beg < 0) {
            beg += RARRAY(ary)->len;
        }
        return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
        rb_scan_args(argc, argv, "11", 0, 0);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
        return rb_ary_entry(ary, FIX2LONG(arg));
    }
    if (SYMBOL_P(arg)) {
        rb_raise(rb_eTypeError, "Symbol as array index");
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY(ary)->len, 0)) {
      case Qfalse:
        break;
      case Qnil:
        return Qnil;
      default:
        return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}
            
array[index] = obj → obj click to toggle source
array[start, length] = obj or an_array or nil → obj or an_array or nil
array[range] = obj or an_array or nil → obj or an_array or nil

Element Assignment—Sets the element at index, or replaces a subarray starting at start and continuing for length elements, or replaces a subarray specified by range. If indices are greater than the current capacity of the array, the array grows automatically. A negative indices will count backward from the end of the array. Inserts elements if length is zero. If nil is used in the second and third form, deletes elements from self. An IndexError is raised if a negative index points past the beginning of the array. See also Array#push, and Array#unshift.

a = Array.new
a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
a[0..2] = "A"               #=> ["A", "4"]
a[-1]   = "Z"               #=> ["A", "Z"]
a[1..-1] = nil              #=> ["A"]
 
               static VALUE
rb_ary_aset(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long offset, beg, len;

    if (argc == 3) {
        if (SYMBOL_P(argv[0])) {
            rb_raise(rb_eTypeError, "Symbol as array index");
        }
        if (SYMBOL_P(argv[1])) {
            rb_raise(rb_eTypeError, "Symbol as subarray length");
        }
        rb_ary_splice(ary, NUM2LONG(argv[0]), NUM2LONG(argv[1]), argv[2]);
        return argv[2];
    }
    if (argc != 2) {
        rb_raise(rb_eArgError, "wrong number of arguments (%d for 2)", argc);
    }
    if (FIXNUM_P(argv[0])) {
        offset = FIX2LONG(argv[0]);
        goto fixnum;
    }
    if (SYMBOL_P(argv[0])) {
        rb_raise(rb_eTypeError, "Symbol as array index");
    }
    if (rb_range_beg_len(argv[0], &beg, &len, RARRAY(ary)->len, 1)) {
        /* check if idx is Range */
        rb_ary_splice(ary, beg, len, argv[1]);
        return argv[1];
    }

    offset = NUM2LONG(argv[0]);
fixnum:
    rb_ary_store(ary, offset, argv[1]);
    return argv[1];
}
            
assoc(obj) → an_array or nil click to toggle source

Searches through an array whose elements are also arrays comparing obj with the first element of each contained array using obj.==. Returns the first contained array that matches (that is, the first associated array), or nil if no match is found. See also Array#rassoc.

s1 = [ "colors", "red", "blue", "green" ]
s2 = [ "letters", "a", "b", "c" ]
s3 = "foo"
a  = [ s1, s2, s3 ]
a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
a.assoc("foo")      #=> nil
 
               VALUE
rb_ary_assoc(ary, key)
    VALUE ary, key;
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY(ary)->len; ++i) {
        v = rb_check_array_type(RARRAY(ary)->ptr[i]);
        if (!NIL_P(v) && RARRAY(v)->len > 0 &&
            rb_equal(RARRAY(v)->ptr[0], key))
            return v;
    }
    return Qnil;
}
            
at(index) → obj or nil click to toggle source

Returns the element at index. A negative index counts from the end of self. Returns nil if the index is out of range. See also Array#[]. (Array#at is slightly faster than Array#[], as it does not accept ranges and so on.)

a = [ "a", "b", "c", "d", "e" ]
a.at(0)     #=> "a"
a.at(-1)    #=> "e"
 
               static VALUE
rb_ary_at(ary, pos)
    VALUE ary, pos;
{
    return rb_ary_entry(ary, NUM2LONG(pos));
}
            
choice → obj click to toggle source

Choose a random element from an array.

 
               static VALUE
rb_ary_choice(ary)
    VALUE ary;
{
    long i, j;

    i = RARRAY(ary)->len;
    if (i == 0) return Qnil;
    j = rb_genrand_real()*i;
    return RARRAY(ary)->ptr[j];
}
            
clear → array click to toggle source

Removes all elements from self.

a = [ "a", "b", "c", "d", "e" ]
a.clear    #=> [ ]
 
               VALUE
rb_ary_clear(ary)
    VALUE ary;
{
    rb_ary_modify(ary);
    RARRAY(ary)->len = 0;
    if (ARY_DEFAULT_SIZE * 2 < RARRAY(ary)->aux.capa) {
        REALLOC_N(RARRAY(ary)->ptr, VALUE, ARY_DEFAULT_SIZE * 2);
        RARRAY(ary)->aux.capa = ARY_DEFAULT_SIZE * 2;
    }
    return ary;
}
            
collect {|item| block } → an_array click to toggle source

Invokes block once for each element of self. Creates a new array containing the values returned by the block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect {|x| x + "!" }   #=> ["a!", "b!", "c!", "d!"]
a                          #=> ["a", "b", "c", "d"]
 
               static VALUE
rb_ary_collect(ary)
    VALUE ary;
{
    long i;
    VALUE collect;

    if (!rb_block_given_p()) {
        return rb_ary_new4(RARRAY(ary)->len, RARRAY(ary)->ptr);
    }

    collect = rb_ary_new2(RARRAY(ary)->len);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        rb_ary_push(collect, rb_yield(RARRAY(ary)->ptr[i]));
    }
    return collect;
}
            
collect! {|item| block } → array click to toggle source

Invokes the block once for each element of self, replacing the element with the value returned by block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect! {|x| x + "!" }
a             #=>  [ "a!", "b!", "c!", "d!" ]
 
               static VALUE
rb_ary_collect_bang(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        rb_ary_store(ary, i, rb_yield(RARRAY(ary)->ptr[i]));
    }
    return ary;
}
            
combination(n) { |c| block } → ary click to toggle source
combination(n) → enumerator

When invoked with a block, yields all combinations of length n of elements from ary and then returns ary itself. The implementation makes no guarantees about the order in which the combinations are yielded.

When invoked without a block, returns an enumerator object instead.

Examples:

a = [1, 2, 3, 4]
a.combination(1).to_a  #=> [[1],[2],[3],[4]]
a.combination(2).to_a  #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
a.combination(3).to_a  #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]]
a.combination(4).to_a  #=> [[1,2,3,4]]
a.combination(0).to_a  #=> [[]] # one combination of length 0
a.combination(5).to_a  #=> []   # no combinations of length 5
 
               static VALUE
rb_ary_combination(ary, num)
    VALUE ary;
    VALUE num;
{
    long n, i, len;

    n = NUM2LONG(num);
    RETURN_ENUMERATOR(ary, 1, &num);
    len = RARRAY(ary)->len;
    if (n < 0 || len < n) {
        /* yield nothing */
    }
    else if (n == 0) {
        rb_yield(rb_ary_new2(0));
    }
    else if (n == 1) {
        for (i = 0; i < len; i++) {
            rb_yield(rb_ary_new3(1, RARRAY(ary)->ptr[i]));
        }
    }
    else {
        volatile VALUE t0 = tmpbuf(n+1, sizeof(long));
        long *stack = (long*)RSTRING(t0)->ptr;
        long nlen = combi_len(len, n);
        volatile VALUE cc = rb_ary_new2(n);
        VALUE *chosen = RARRAY(cc)->ptr;
        long lev = 0;

        RBASIC(cc)->klass = 0;
        MEMZERO(stack, long, n);
        stack[0] = -1;
        for (i = 0; i < nlen; i++) {
            chosen[lev] = RARRAY(ary)->ptr[stack[lev+1]];
            for (lev++; lev < n; lev++) {
                chosen[lev] = RARRAY(ary)->ptr[stack[lev+1] = stack[lev]+1];
            }
            rb_yield(rb_ary_new4(n, chosen));
            do {
                stack[lev--]++;
            } while (lev && (stack[lev+1]+n == len+lev+1));
        }
    }
    return ary;
}
            
compact → an_array click to toggle source

Returns a copy of self with all nil elements removed.

[ "a", nil, "b", nil, "c", nil ].compact
                  #=> [ "a", "b", "c" ]
 
               static VALUE
rb_ary_compact(ary)
    VALUE ary;
{
    ary = rb_ary_dup(ary);
    rb_ary_compact_bang(ary);
    return ary;
}
            
compact! → array or nil click to toggle source

Removes nil elements from array. Returns nil if no changes were made.

[ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
[ "a", "b", "c" ].compact!           #=> nil
 
               static VALUE
rb_ary_compact_bang(ary)
    VALUE ary;
{
    VALUE *p, *t, *end;

    rb_ary_modify(ary);
    p = t = RARRAY(ary)->ptr;
    end = p + RARRAY(ary)->len;
    
    while (t < end) {
        if (NIL_P(*t)) t++;
        else *p++ = *t++;
    }
    if (RARRAY(ary)->len == (p - RARRAY(ary)->ptr)) {
        return Qnil;
    }
    RARRAY(ary)->len = RARRAY(ary)->aux.capa = (p - RARRAY(ary)->ptr);
    REALLOC_N(RARRAY(ary)->ptr, VALUE, RARRAY(ary)->len);

    return ary;
}
            
concat(other_array) → array click to toggle source

Appends the elements in other_array to self.

[ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
 
               VALUE
rb_ary_concat(x, y)
    VALUE x, y;
{
    y = to_ary(y);
    if (RARRAY(y)->len > 0) {
        rb_ary_splice(x, RARRAY(x)->len, 0, y);
    }
    return x;
}
            
count → int click to toggle source
count(obj) → int
count { |item| block } → int

Returns the number of elements. If an argument is given, counts the number of elements which equals to obj. If a block is given, counts the number of elements yielding a true value.

ary = [1, 2, 4, 2]
ary.count             # => 4
ary.count(2)          # => 2
ary.count{|x|x%2==0}  # => 3
 
               static VALUE
rb_ary_count(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long n = 0;

    if (argc == 0) {
        VALUE *p, *pend;

        if (!rb_block_given_p())
            return LONG2NUM(RARRAY_LEN(ary));

        for (p = RARRAY_PTR(ary), pend = p + RARRAY_LEN(ary); p < pend; p++) {
            if (RTEST(rb_yield(*p))) n++;
        }
    }
    else {
        VALUE obj, *p, *pend;

        rb_scan_args(argc, argv, "1", &obj);
        if (rb_block_given_p()) {
            rb_warn("given block not used");
        }
        for (p = RARRAY_PTR(ary), pend = p + RARRAY_LEN(ary); p < pend; p++) {
            if (rb_equal(*p, obj)) n++;
        }
    }

    return LONG2NUM(n);
}
            
cycle {|obj| block } click to toggle source
cycle(n) {|obj| block }

Calls block for each element repeatedly n times or forever if none or nil is given. If a non-positive number is given or the array is empty, does nothing. Returns nil if the loop has finished without getting interrupted.

a = ["a", "b", "c"]
a.cycle {|x| puts x }  # print, a, b, c, a, b, c,.. forever.
a.cycle(2) {|x| puts x }  # print, a, b, c, a, b, c.
 
               static VALUE
rb_ary_cycle(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long n, i;
    VALUE nv = Qnil;

    rb_scan_args(argc, argv, "01", &nv);

    RETURN_ENUMERATOR(ary, argc, argv);
    if (NIL_P(nv)) {
        n = -1;
    }
    else {
        n = NUM2LONG(nv);
        if (n <= 0) return Qnil;
    }

    while (RARRAY(ary)->len > 0 && (n < 0 || 0 < n--)) {
        for (i=0; i<RARRAY(ary)->len; i++) {
            rb_yield(RARRAY(ary)->ptr[i]);
        }
    }
    return Qnil;
}
            
delete(obj) → obj or nil click to toggle source
delete(obj) { block } → obj or nil

Deletes items from self that are equal to obj. If the item is not found, returns nil. If the optional code block is given, returns the result of block if the item is not found.

a = [ "a", "b", "b", "b", "c" ]
a.delete("b")                   #=> "b"
a                               #=> ["a", "c"]
a.delete("z")                   #=> nil
a.delete("z") { "not found" }   #=> "not found"
 
               VALUE
rb_ary_delete(ary, item)
    VALUE ary;
    VALUE item;
{
    long i1, i2;

    for (i1 = i2 = 0; i1 < RARRAY(ary)->len; i1++) {
        VALUE e = RARRAY(ary)->ptr[i1];

        if (rb_equal(e, item)) continue;
        if (i1 != i2) {
            rb_ary_store(ary, i2, e);
        }
        i2++;
    }
    if (RARRAY(ary)->len == i2) {
        if (rb_block_given_p()) {
            return rb_yield(item);
        }
        return Qnil;
    }

    rb_ary_modify(ary);
    if (RARRAY(ary)->len > i2) {
        RARRAY(ary)->len = i2;
        if (i2 * 2 < RARRAY(ary)->aux.capa &&
            RARRAY(ary)->aux.capa > ARY_DEFAULT_SIZE) {
            REALLOC_N(RARRAY(ary)->ptr, VALUE, i2 * 2);
            RARRAY(ary)->aux.capa = i2 * 2;
        }
    }

    return item;
}
            
delete_at(index) → obj or nil click to toggle source

Deletes the element at the specified index, returning that element, or nil if the index is out of range. See also Array#slice!.

a = %w( ant bat cat dog )
a.delete_at(2)    #=> "cat"
a                 #=> ["ant", "bat", "dog"]
a.delete_at(99)   #=> nil
 
               static VALUE
rb_ary_delete_at_m(ary, pos)
    VALUE ary, pos;
{
    return rb_ary_delete_at(ary, NUM2LONG(pos));
}
            
delete_if {|item| block } → array click to toggle source

Deletes every element of self for which block evaluates to true.

a = [ "a", "b", "c" ]
a.delete_if {|x| x >= "b" }   #=> ["a"]
 
               static VALUE
rb_ary_delete_if(ary)
    VALUE ary;
{
    RETURN_ENUMERATOR(ary, 0, 0);
    rb_ary_reject_bang(ary);
    return ary;
}
            
drop(n) => array click to toggle source

Drops first n elements from ary, and returns rest elements in an array.

a = [1, 2, 3, 4, 5, 0]
a.drop(3)             # => [4, 5, 0]
 
               static VALUE
rb_ary_drop(ary, n)
    VALUE ary;
    VALUE n;
{
    VALUE result;
    long pos = NUM2LONG(n);
    if (pos < 0) {
        rb_raise(rb_eArgError, "attempt to drop negative size");
    }

    result = rb_ary_subseq(ary, pos, RARRAY(ary)->len);
    if (result == Qnil) result = rb_ary_new();
    return result;
}
            
drop_while {|arr| block } => array click to toggle source

Drops elements up to, but not including, the first element for which the block returns nil or false and returns an array containing the remaining elements.

a = [1, 2, 3, 4, 5, 0]
a.drop_while {|i| i < 3 }   # => [3, 4, 5, 0]
 
               static VALUE
rb_ary_drop_while(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        if (!RTEST(rb_yield(RARRAY(ary)->ptr[i]))) break;
    }
    return rb_ary_drop(ary, LONG2FIX(i));
}
            
each {|item| block } → array click to toggle source

Calls block once for each element in self, passing that element as a parameter.

a = [ "a", "b", "c" ]
a.each {|x| print x, " -- " }

produces:

a -- b -- c --
 
               VALUE
rb_ary_each(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i=0; i<RARRAY(ary)->len; i++) {
        rb_yield(RARRAY(ary)->ptr[i]);
    }
    return ary;
}
            
each_index {|index| block } → array click to toggle source

Same as Array#each, but passes the index of the element instead of the element itself.

a = [ "a", "b", "c" ]
a.each_index {|x| print x, " -- " }

produces:

0 -- 1 -- 2 --
 
               static VALUE
rb_ary_each_index(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i=0; i<RARRAY(ary)->len; i++) {
        rb_yield(LONG2NUM(i));
    }
    return ary;
}
            
empty? → true or false click to toggle source

Returns true if self array contains no elements.

[].empty?   #=> true
 
               static VALUE
rb_ary_empty_p(ary)
    VALUE ary;
{
    if (RARRAY(ary)->len == 0)
        return Qtrue;
    return Qfalse;
}
            
eql?(other) → true or false click to toggle source

Returns true if array and other are the same object, or are both arrays with the same content.

 
               static VALUE
rb_ary_eql(ary1, ary2)
    VALUE ary1, ary2;
{
    if (ary1 == ary2) return Qtrue;
    if (TYPE(ary2) != T_ARRAY) return Qfalse;
    if (RARRAY(ary1)->len != RARRAY(ary2)->len) return Qfalse;
    return rb_exec_recursive(recursive_eql, ary1, ary2);
}
            
fetch(index) → obj click to toggle source
fetch(index, default ) → obj
fetch(index) {|index| block } → obj

Tries to return the element at position index. If the index lies outside the array, the first form throws an IndexError exception, the second form returns default, and the third form returns the value of invoking the block, passing in the index. Negative values of index count from the end of the array.

a = [ 11, 22, 33, 44 ]
a.fetch(1)               #=> 22
a.fetch(-1)              #=> 44
a.fetch(4, 'cat')        #=> "cat"
a.fetch(4) { |i| i*i }   #=> 16
 
               static VALUE
rb_ary_fetch(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE pos, ifnone;
    long block_given;
    long idx;

    rb_scan_args(argc, argv, "11", &pos, &ifnone);
    block_given = rb_block_given_p();
    if (block_given && argc == 2) {
        rb_warn("block supersedes default value argument");
    }
    idx = NUM2LONG(pos);

    if (idx < 0) {
        idx +=  RARRAY(ary)->len;
    }
    if (idx < 0 || RARRAY(ary)->len <= idx) {
        if (block_given) return rb_yield(pos);
        if (argc == 1) {
            rb_raise(rb_eIndexError, "index %ld out of array", idx);
        }
        return ifnone;
    }
    return RARRAY(ary)->ptr[idx];
}
            
fill(obj) → array click to toggle source
fill(obj, start [, length]) → array
fill(obj, range ) → array
fill {|index| block } → array
fill(start [, length] ) {|index| block } → array
fill(range) {|index| block } → array

The first three forms set the selected elements of self (which may be the entire array) to obj. A start of nil is equivalent to zero. A length of nil is equivalent to self.length. The last three forms fill the array with the value of the block. The block is passed the absolute index of each element to be filled.

a = [ "a", "b", "c", "d" ]
a.fill("x")              #=> ["x", "x", "x", "x"]
a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
a.fill {|i| i*i}         #=> [0, 1, 4, 9]
a.fill(-2) {|i| i*i*i}   #=> [0, 1, 8, 27]
 
               static VALUE
rb_ary_fill(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE item, arg1, arg2;
    long beg = 0, end = 0, len = 0;
    VALUE *p, *pend;
    int block_p = Qfalse;

    if (rb_block_given_p()) {
        block_p = Qtrue;
        rb_scan_args(argc, argv, "02", &arg1, &arg2);
        argc += 1;             /* hackish */
    }
    else {
        rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
    }
    switch (argc) {
      case 1:
        beg = 0;
        len = RARRAY(ary)->len;
        break;
      case 2:
        if (rb_range_beg_len(arg1, &beg, &len, RARRAY(ary)->len, 1)) {
            break;
        }
        /* fall through */
      case 3:
        beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
        if (beg < 0) {
            beg = RARRAY(ary)->len + beg;
            if (beg < 0) beg = 0;
        }
        len = NIL_P(arg2) ? RARRAY(ary)->len - beg : NUM2LONG(arg2);
        break;
    }
    rb_ary_modify(ary);
    if (len < 0) {
        return ary;
    }
    if (beg >= ARY_MAX_SIZE || len > ARY_MAX_SIZE - beg) {
        rb_raise(rb_eArgError, "argument too big");
    }
    end = beg + len;
    if (end > RARRAY(ary)->len) {
        if (end >= RARRAY(ary)->aux.capa) {
            REALLOC_N(RARRAY(ary)->ptr, VALUE, end);
            RARRAY(ary)->aux.capa = end;
        }
        rb_mem_clear(RARRAY(ary)->ptr + RARRAY(ary)->len, end - RARRAY(ary)->len);
        RARRAY(ary)->len = end;
    }

    if (block_p) {
        VALUE v;
        long i;

        for (i=beg; i<end; i++) {
            v = rb_yield(LONG2NUM(i));
            if (i>=RARRAY(ary)->len) break;
            RARRAY(ary)->ptr[i] = v;
        }
    }
    else {
        p = RARRAY(ary)->ptr + beg;
        pend = p + len;
        while (p < pend) {
            *p++ = item;
        }
    }
    return ary;
}
            
index(obj) → int or nil click to toggle source
index {|item| block} → int or nil

Returns the index of the first object in self such that is == to obj. If a block is given instead of an argument, returns first object for which block is true. Returns nil if no match is found.

a = [ "a", "b", "c" ]
a.index("b")        #=> 1
a.index("z")        #=> nil
a.index{|x|x=="b"}  #=> 1

This is an alias of #find_index.

 
               static VALUE
rb_ary_index(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE val;
    long i;

    if (argc  == 0) {
        RETURN_ENUMERATOR(ary, 0, 0);
        for (i=0; i<RARRAY(ary)->len; i++) {
            if (RTEST(rb_yield(RARRAY(ary)->ptr[i]))) {
                return LONG2NUM(i);
            }
        }
        return Qnil;
    }
    rb_scan_args(argc, argv, "01", &val);
    for (i=0; i<RARRAY(ary)->len; i++) {
        if (rb_equal(RARRAY(ary)->ptr[i], val))
            return LONG2NUM(i);
    }
    return Qnil;
}
            
first → obj or nil click to toggle source
first(n) → an_array

Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns nil, and the second form returns an empty array.

a = [ "q", "r", "s", "t" ]
a.first    #=> "q"
a.first(1) #=> ["q"]
a.first(3) #=> ["q", "r", "s"]
 
               static VALUE
rb_ary_first(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    if (argc == 0) {
        if (RARRAY(ary)->len == 0) return Qnil;
        return RARRAY(ary)->ptr[0];
    }
    else {
        return ary_shared_first(argc, argv, ary, Qfalse);
    }
}
            
flatten → an_array click to toggle source
flatten(level) → an_array

Returns a new array that is a one-dimensional flattening of this array (recursively). That is, for every element that is an array, extract its elements into the new array. If the optional level argument determines the level of recursion to flatten.

s = [ 1, 2, 3 ]           #=> [1, 2, 3]
t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten(1)              #=> [1, 2, 3, [4, 5]]
 
               static VALUE
rb_ary_flatten(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return ary;

    result = flatten(ary, level, &mod);
    if (OBJ_TAINTED(ary)) OBJ_TAINT(result);

    return result;
}
            
flatten! → array or nil click to toggle source
flatten!(level) → array or nil

Flattens self in place. Returns nil if no modifications were made (i.e., array contains no subarrays.) If the optional level argument determines the level of recursion to flatten.

a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!   #=> [1, 2, 3, 4, 5]
a.flatten!   #=> nil
a            #=> [1, 2, 3, 4, 5]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!(1) #=> [1, 2, 3, [4, 5]]
 
               static VALUE
rb_ary_flatten_bang(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return ary;

    result = flatten(ary, level, &mod);
    if (mod == 0) return Qnil;
    rb_ary_replace(ary, result);

    return ary;
}
            
frozen? → true or false click to toggle source

Return true if this array is frozen (or temporarily frozen while being sorted).

 
               static VALUE
rb_ary_frozen_p(ary)
    VALUE ary;
{
    if (OBJ_FROZEN(ary)) return Qtrue;
    if (FL_TEST(ary, ARY_TMPLOCK)) return Qtrue;
    return Qfalse;
}
            
hash → fixnum click to toggle source

Compute a hash-code for this array. Two arrays with the same content will have the same hash code (and will compare using eql?).

 
               static VALUE
rb_ary_hash(ary)
    VALUE ary;
{
    return rb_exec_recursive(recursive_hash, ary, 0);
}
            
include?(obj) → true or false click to toggle source

Returns true if the given object is present in self (that is, if any object == anObject), false otherwise.

a = [ "a", "b", "c" ]
a.include?("b")   #=> true
a.include?("z")   #=> false
 
               VALUE
rb_ary_includes(ary, item)
    VALUE ary;
    VALUE item;
{
    long i;
    
    for (i=0; i<RARRAY(ary)->len; i++) {
        if (rb_equal(RARRAY(ary)->ptr[i], item)) {
            return Qtrue;
        }
    }
    return Qfalse;
}
            
index(obj) → int or nil click to toggle source
index {|item| block} → int or nil

Returns the index of the first object in self such that is == to obj. If a block is given instead of an argument, returns first object for which block is true. Returns nil if no match is found.

a = [ "a", "b", "c" ]
a.index("b")        #=> 1
a.index("z")        #=> nil
a.index{|x|x=="b"}  #=> 1

This is an alias of #find_index.

 
               static VALUE
rb_ary_index(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE val;
    long i;

    if (argc  == 0) {
        RETURN_ENUMERATOR(ary, 0, 0);
        for (i=0; i<RARRAY(ary)->len; i++) {
            if (RTEST(rb_yield(RARRAY(ary)->ptr[i]))) {
                return LONG2NUM(i);
            }
        }
        return Qnil;
    }
    rb_scan_args(argc, argv, "01", &val);
    for (i=0; i<RARRAY(ary)->len; i++) {
        if (rb_equal(RARRAY(ary)->ptr[i], val))
            return LONG2NUM(i);
    }
    return Qnil;
}
            
indexes( i1, i2, ... iN ) → an_array click to toggle source

Deprecated; use Array#values_at.

 
               static VALUE
rb_ary_indexes(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE new_ary;
    long i;

    rb_warn("Array#%s is deprecated; use Array#values_at", rb_id2name(rb_frame_last_func()));
    new_ary = rb_ary_new2(argc);
    for (i=0; i<argc; i++) {
        rb_ary_push(new_ary, rb_ary_aref(1, argv+i, ary));
    }

    return new_ary;
}
            
indices( i1, i2, ... iN ) → an_array click to toggle source

Deprecated; use Array#values_at.

 
               static VALUE
rb_ary_indexes(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE new_ary;
    long i;

    rb_warn("Array#%s is deprecated; use Array#values_at", rb_id2name(rb_frame_last_func()));
    new_ary = rb_ary_new2(argc);
    for (i=0; i<argc; i++) {
        rb_ary_push(new_ary, rb_ary_aref(1, argv+i, ary));
    }

    return new_ary;
}
            
replace(other_array) → array click to toggle source

Replaces the contents of self with the contents of other_array, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]
 
               static VALUE
rb_ary_replace(copy, orig)
    VALUE copy, orig;
{
    VALUE shared;

    rb_ary_modify(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;
    shared = ary_make_shared(orig);
    if (RARRAY(copy)->ptr && !FL_TEST(copy, ELTS_SHARED))
        free(RARRAY(copy)->ptr);
    RARRAY(copy)->ptr = RARRAY(orig)->ptr;
    RARRAY(copy)->len = RARRAY(orig)->len;
    RARRAY(copy)->aux.shared = shared;
    FL_SET(copy, ELTS_SHARED);

    return copy;
}
            
insert(index, obj...) → array click to toggle source

Inserts the given values before the element with the given index (which may be negative).

a = %w{ a b c d }
a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]
 
               static VALUE
rb_ary_insert(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long pos;

    if (argc == 1) return ary;
    if (argc < 1) {
        rb_raise(rb_eArgError, "wrong number of arguments (at least 1)");
    }
    pos = NUM2LONG(argv[0]);
    if (pos == -1) {
        pos = RARRAY(ary)->len;
    }
    if (pos < 0) {
        pos++;
    }
    rb_ary_splice(ary, pos, 0, rb_ary_new4(argc - 1, argv + 1));
    return ary;
}
            
inspect → string click to toggle source

Create a printable version of array.

 
               static VALUE
rb_ary_inspect(ary)
    VALUE ary;
{
    if (RARRAY(ary)->len == 0) return rb_str_new2("[]");
    if (rb_inspecting_p(ary)) return rb_str_new2("[...]");
    return rb_protect_inspect(inspect_ary, ary, 0);
}
            
join(sep=$,) → str click to toggle source

Returns a string created by converting each element of the array to a string, separated by sep.

[ "a", "b", "c" ].join        #=> "abc"
[ "a", "b", "c" ].join("-")   #=> "a-b-c"
 
               static VALUE
rb_ary_join_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE sep;

    rb_scan_args(argc, argv, "01", &sep);
    if (NIL_P(sep)) sep = rb_output_fs;
    
    return rb_ary_join(ary, sep);
}
            
last → obj or nil click to toggle source
last(n) → an_array

Returns the last element(s) of self. If the array is empty, the first form returns nil.

[ "w", "x", "y", "z" ].last   #=> "z"
 
               static VALUE
rb_ary_last(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    if (argc == 0) {
        if (RARRAY(ary)->len == 0) return Qnil;
        return RARRAY(ary)->ptr[RARRAY(ary)->len-1];
    }
    else {
        return ary_shared_first(argc, argv, ary, Qtrue);
    }
}
            
length → int click to toggle source

Returns the number of elements in self. May be zero.

[ 1, 2, 3, 4, 5 ].length   #=> 5
 
               static VALUE
rb_ary_length(ary)
    VALUE ary;
{
    return LONG2NUM(RARRAY(ary)->len);
}
            
Also aliased as: size
map {|item| block } → an_array click to toggle source

Invokes block once for each element of self. Creates a new array containing the values returned by the block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect {|x| x + "!" }   #=> ["a!", "b!", "c!", "d!"]
a                          #=> ["a", "b", "c", "d"]
 
               static VALUE
rb_ary_collect(ary)
    VALUE ary;
{
    long i;
    VALUE collect;

    if (!rb_block_given_p()) {
        return rb_ary_new4(RARRAY(ary)->len, RARRAY(ary)->ptr);
    }

    collect = rb_ary_new2(RARRAY(ary)->len);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        rb_ary_push(collect, rb_yield(RARRAY(ary)->ptr[i]));
    }
    return collect;
}
            
map! {|item| block } → array click to toggle source

Invokes the block once for each element of self, replacing the element with the value returned by block. See also Enumerable#collect.

a = [ "a", "b", "c", "d" ]
a.collect! {|x| x + "!" }
a             #=>  [ "a!", "b!", "c!", "d!" ]
 
               static VALUE
rb_ary_collect_bang(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        rb_ary_store(ary, i, rb_yield(RARRAY(ary)->ptr[i]));
    }
    return ary;
}
            
nitems → int click to toggle source

Returns the number of non-nil elements in self.

May be zero.

[ 1, nil, 3, nil, 5 ].nitems   #=> 3
 
               static VALUE
rb_ary_nitems(ary)
    VALUE ary;
{
    long n = 0;
    VALUE *p, *pend;

    for (p = RARRAY(ary)->ptr, pend = p + RARRAY(ary)->len; p < pend; p++) {
        if (!NIL_P(*p)) n++;
    }
    return LONG2NUM(n);
}
            
pack ( aTemplateString ) → aBinaryString click to toggle source

Packs the contents of arr into a binary sequence according to the directives in aTemplateString (see the table below) Directives “A,” “a,” and “Z” may be followed by a count, which gives the width of the resulting field. The remaining directives also may take a count, indicating the number of array elements to convert. If the count is an asterisk (“*”), all remaining array elements will be converted. Any of the directives “sSiIlL” may be followed by an underscore (“_”) to use the underlying platform’s native size for the specified type; otherwise, they use a platform-independent size. Spaces are ignored in the template string. See also String#unpack.

a = [ "a", "b", "c" ]
n = [ 65, 66, 67 ]
a.pack("A3A3A3")   #=> "a  b  c  "
a.pack("a3a3a3")   #=> "a\000\000b\000\000c\000\000"
n.pack("ccc")      #=> "ABC"

Directives for pack.

Integer   | Array   |
Directive | Element | Meaning
------------------------------------------------------------------------
   C      | Integer | 8-bit unsigned integer (unsigned char)
   S      | Integer | 16-bit unsigned integer, native endian (uint16_t)
   L      | Integer | 32-bit unsigned integer, native endian (uint32_t)
   Q      | Integer | 64-bit unsigned integer, native endian (uint64_t)
          |         |
   c      | Integer | 8-bit signed integer (char)
   s      | Integer | 16-bit signed integer, native endian (int16_t)
   l      | Integer | 32-bit signed integer, native endian (int32_t)
   q      | Integer | 64-bit signed integer, native endian (int64_t)
          |         | 
   S_     | Integer | unsigned short, native endian
   I, I_  | Integer | unsigned int, native endian
   L_     | Integer | unsigned long, native endian
          |         |
   s_     | Integer | signed short, native endian
   i, i_  | Integer | signed int, native endian
   l_     | Integer | signed long, native endian
          |         |
   n      | Integer | 16-bit unsigned integer, network (big-endian) byte order
   N      | Integer | 32-bit unsigned integer, network (big-endian) byte order
   v      | Integer | 16-bit unsigned integer, VAX (little-endian) byte order
   V      | Integer | 32-bit unsigned integer, VAX (little-endian) byte order
          |         |
   U      | Integer | UTF-8 character
   w      | Integer | BER-compressed integer

Float     |         |
Directive |         | Meaning
------------------------------------------------------------------------
   D, d   | Float   | double-precision float, native format
   F, f   | Float   | single-precision float, native format
   E      | Float   | double-precision float, little-endian byte order
   e      | Float   | single-precision float, little-endian byte order
   G      | Float   | double-precision float, network (big-endian) byte order
   g      | Float   | single-precision float, network (big-endian) byte order

String    |         |
Directive |         | Meaning
------------------------------------------------------------------------
   A      | String  | arbitrary binary string (space padded, count is width)
   a      | String  | arbitrary binary string (null padded, count is width)
   Z      | String  | same as ``a'', except that null is added with *
   B      | String  | bit string (MSB first)
   b      | String  | bit string (LSB first)
   H      | String  | hex string (high nibble first)
   h      | String  | hex string (low nibble first)
   u      | String  | UU-encoded string
   M      | String  | quoted printable, MIME encoding (see RFC2045)
   m      | String  | base64 encoded string (see RFC 2045, count is width)
   P      | String  | pointer to a structure (fixed-length string)
   p      | String  | pointer to a null-terminated string

Misc.     |         |
Directive |         | Meaning
------------------------------------------------------------------------
   @      | ---     | moves to absolute position
   X      | ---     | back up a byte
   x      | ---     | null byte
 
               static VALUE
pack_pack(ary, fmt)
    VALUE ary, fmt;
{
    static const char nul10[] = "\0\0\0\0\0\0\0\0\0\0";
    static const char spc10[] = "          ";
    char *p, *pend;
    VALUE res, from, associates = 0;
    char type;
    long items, len, idx, plen;
    const char *ptr;
#ifdef NATINT_PACK
    int natint;         /* native integer */
#endif
    int signed_p, integer_size, bigendian_p;

    StringValue(fmt);
    p = RSTRING(fmt)->ptr;
    pend = p + RSTRING(fmt)->len;
    res = rb_str_buf_new(0);

    items = RARRAY(ary)->len;
    idx = 0;

#define TOO_FEW (rb_raise(rb_eArgError, toofew), 0)
#define THISFROM (items > 0 ? RARRAY(ary)->ptr[idx] : TOO_FEW)
#define NEXTFROM (items-- > 0 ? RARRAY(ary)->ptr[idx++] : TOO_FEW)

    while (p < pend) {
        if (RSTRING(fmt)->ptr + RSTRING(fmt)->len != pend) {
            rb_raise(rb_eRuntimeError, "format string modified");
        }
        type = *p++;           /* get data type */
#ifdef NATINT_PACK
        natint = 0;
#endif

        if (ISSPACE(type)) continue;
        if (type == '#') {
            while ((p < pend) && (*p != '\n')) {
                p++;
            }
            continue;
        }
        if (*p == '_' || *p == '!') {
            const char *natstr = "sSiIlL";

            if (strchr(natstr, type)) {
#ifdef NATINT_PACK
                natint = 1;
#endif
                p++;
            }
            else {
                rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, natstr);
            }
        }
        if (*p == '*') {       /* set data length */
            len = strchr("@Xxu", type) ? 0
                : strchr("PMm", type) ? 1
                : items;
            p++;
        }
        else if (ISDIGIT(*p)) {
            len = strtoul(p, (char**)&p, 10);
        }
        else {
            len = 1;
        }

        switch (type) {
          case 'A': case 'a': case 'Z':
          case 'B': case 'b':
          case 'H': case 'h':
            from = NEXTFROM;
            if (NIL_P(from)) {
                ptr = "";
                plen = 0;
            }
            else {
                StringValue(from);
                ptr = RSTRING(from)->ptr;
                plen = RSTRING(from)->len;
                OBJ_INFECT(res, from);
            }

            if (p[-1] == '*')
                len = plen;

            switch (type) {
              case 'a':                /* arbitrary binary string (null padded)  */
              case 'A':                /* ASCII string (space padded) */
              case 'Z':                /* null terminated ASCII string  */
                if (plen >= len) {
                    rb_str_buf_cat(res, ptr, len);
                    if (p[-1] == '*' && type == 'Z')
                        rb_str_buf_cat(res, nul10, 1);
                }
                else {
                    rb_str_buf_cat(res, ptr, plen);
                    len -= plen;
                    while (len >= 10) {
                        rb_str_buf_cat(res, (type == 'A')?spc10:nul10, 10);
                        len -= 10;
                    }
                    rb_str_buf_cat(res, (type == 'A')?spc10:nul10, len);
                }
                break;

              case 'b':                /* bit string (ascending) */
                {
                    int byte = 0;
                    long i, j = 0;

                    if (len > plen) {
                        j = (len - plen + 1)/2;
                        len = plen;
                    }
                    for (i=0; i++ < len; ptr++) {
                        if (*ptr & 1)
                            byte |= 128;
                        if (i & 7)
                            byte >>= 1;
                        else {
                            char c = byte & 0xff;
                            rb_str_buf_cat(res, &c, 1);
                            byte = 0;
                        }
                    }
                    if (len & 7) {
                        char c;
                        byte >>= 7 - (len & 7);
                        c = byte & 0xff;
                        rb_str_buf_cat(res, &c, 1);
                    }
                    len = j;
                    goto grow;
                }
                break;

              case 'B':                /* bit string (descending) */
                {
                    int byte = 0;
                    long i, j = 0;

                    if (len > plen) {
                        j = (len - plen + 1)/2;
                        len = plen;
                    }
                    for (i=0; i++ < len; ptr++) {
                        byte |= *ptr & 1;
                        if (i & 7)
                            byte <<= 1;
                        else {
                            char c = byte & 0xff;
                            rb_str_buf_cat(res, &c, 1);
                            byte = 0;
                        }
                    }
                    if (len & 7) {
                        char c;
                        byte <<= 7 - (len & 7);
                        c = byte & 0xff;
                        rb_str_buf_cat(res, &c, 1);
                    }
                    len = j;
                    goto grow;
                }
                break;

              case 'h':                /* hex string (low nibble first) */
                {
                    int byte = 0;
                    long i, j = 0;

                    if (len > plen) {
                        j = (len + 1) / 2 - (plen + 1) / 2;
                        len = plen;
                    }
                    for (i=0; i++ < len; ptr++) {
                        if (ISALPHA(*ptr))
                            byte |= (((*ptr & 15) + 9) & 15) << 4;
                        else
                            byte |= (*ptr & 15) << 4;
                        if (i & 1)
                            byte >>= 4;
                        else {
                            char c = byte & 0xff;
                            rb_str_buf_cat(res, &c, 1);
                            byte = 0;
                        }
                    }
                    if (len & 1) {
                        char c = byte & 0xff;
                        rb_str_buf_cat(res, &c, 1);
                    }
                    len = j;
                    goto grow;
                }
                break;

              case 'H':                /* hex string (high nibble first) */
                {
                    int byte = 0;
                    long i, j = 0;

                    if (len > plen) {
                        j = (len + 1) / 2 - (plen + 1) / 2;
                        len = plen;
                    }
                    for (i=0; i++ < len; ptr++) {
                        if (ISALPHA(*ptr))
                            byte |= ((*ptr & 15) + 9) & 15;
                        else
                            byte |= *ptr & 15;
                        if (i & 1)
                            byte <<= 4;
                        else {
                            char c = byte & 0xff;
                            rb_str_buf_cat(res, &c, 1);
                            byte = 0;
                        }
                    }
                    if (len & 1) {
                        char c = byte & 0xff;
                        rb_str_buf_cat(res, &c, 1);
                    }
                    len = j;
                    goto grow;
                }
                break;
            }
            break;

          case 'c':            /* signed char */
          case 'C':            /* unsigned char */
            while (len-- > 0) {
                char c;

                from = NEXTFROM;
                c = num2i32(from);
                rb_str_buf_cat(res, &c, sizeof(char));
            }
            break;

          case 's':            /* signed short */
            signed_p = 1;
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'S':            /* unsigned short */
            signed_p = 0;
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'i':            /* signed int */
            signed_p = 1;
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'I':            /* unsigned int */
            signed_p = 0;
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'l':            /* signed long */
            signed_p = 1;
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'L':            /* unsigned long */
            signed_p = 0;
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'q':            /* signed quad (64bit) int */
            signed_p = 1;
            integer_size = 8;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'Q':            /* unsigned quad (64bit) int */
            signed_p = 0;
            integer_size = 8;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

          case 'n':            /* unsigned short (network byte-order)  */
            signed_p = 0;
            integer_size = 2;
            bigendian_p = 1;
            goto pack_integer;

          case 'N':            /* unsigned long (network byte-order) */
            signed_p = 0;
            integer_size = 4;
            bigendian_p = 1;
            goto pack_integer;

          case 'v':            /* unsigned short (VAX byte-order) */
            signed_p = 0;
            integer_size = 2;
            bigendian_p = 0;
            goto pack_integer;

          case 'V':            /* unsigned long (VAX byte-order) */
            signed_p = 0;
            integer_size = 4;
            bigendian_p = 0;
            goto pack_integer;

          pack_integer:
            switch (integer_size) {
#if defined(HAVE_INT16_T) && !defined(FORCE_BIG_PACK)
              case SIZEOF_INT16_T:
                while (len-- > 0) {
                    union {
                        int16_t i;
                        char a[sizeof(int16_t)];
                    } v;

                    from = NEXTFROM;
                    v.i = (int16_t)num2i32(from);
                    if (bigendian_p != BIGENDIAN_P()) v.i = swap16(v.i);
                    rb_str_buf_cat(res, v.a, sizeof(int16_t));
                }
                break;
#endif

#if defined(HAVE_INT32_T) && !defined(FORCE_BIG_PACK)
              case SIZEOF_INT32_T:
                while (len-- > 0) {
                    union {
                        int32_t i;
                        char a[sizeof(int32_t)];
                    } v;

                    from = NEXTFROM;
                    v.i = (int32_t)num2i32(from);
                    if (bigendian_p != BIGENDIAN_P()) v.i = swap32(v.i);
                    rb_str_buf_cat(res, v.a, sizeof(int32_t));
                }
                break;
#endif

#if defined(HAVE_INT64_T) && SIZEOF_LONG == SIZEOF_INT64_T && !defined(FORCE_BIG_PACK)
              case SIZEOF_INT64_T:
                while (len-- > 0) {
                    union {
                        int64_t i;
                        char a[sizeof(int64_t)];
                    } v;

                    from = NEXTFROM;
                    v.i = num2i32(from); /* can return 64bit value if SIZEOF_LONG == SIZEOF_INT64_T */
                    if (bigendian_p != BIGENDIAN_P()) v.i = swap64(v.i);
                    rb_str_buf_cat(res, v.a, sizeof(int64_t));
                }
                break;
#endif

              default:
                if (integer_size > MAX_INTEGER_PACK_SIZE)
                    rb_bug("unexpected intger size for pack: %d", integer_size);
                while (len-- > 0) {
                    union {
                        unsigned long i[(MAX_INTEGER_PACK_SIZE+SIZEOF_LONG-1)/SIZEOF_LONG];
                        char a[(MAX_INTEGER_PACK_SIZE+SIZEOF_LONG-1)/SIZEOF_LONG*SIZEOF_LONG];
                    } v;
                    int num_longs = (integer_size+SIZEOF_LONG-1)/SIZEOF_LONG;
                    int i;

                    from = NEXTFROM;
                    from = rb_to_int(from);
                    if (integer_size == QUAD_SIZE)
                        rb_quad_pack(v.a, from); /* RangeError compatibility for Ruby 1.8. */
                    rb_big_pack(from, v.i, num_longs);
                    if (bigendian_p) {
                        for (i = 0; i < num_longs/2; i++) {
                            unsigned long t = v.i[i];
                            v.i[i] = v.i[num_longs-1-i];
                            v.i[num_longs-1-i] = t;
                        }
                    }
                    if (bigendian_p != BIGENDIAN_P()) {
                        for (i = 0; i < num_longs; i++)
                            v.i[i] = swapl(v.i[i]);
                    }
                    rb_str_buf_cat(res,
                                   bigendian_p ?
                                     v.a + sizeof(long)*num_longs - integer_size :
                                     v.a,
                                   integer_size);
                }
                break;
            }
            break;

          case 'f':            /* single precision float in native format */
          case 'F':            /* ditto */
            while (len-- > 0) {
                float f;

                from = NEXTFROM;
                f = RFLOAT(rb_Float(from))->value;
                rb_str_buf_cat(res, (char*)&f, sizeof(float));
            }
            break;

          case 'e':            /* single precision float in VAX byte-order */
            while (len-- > 0) {
                float f;
                FLOAT_CONVWITH(ftmp);

                from = NEXTFROM;
                f = RFLOAT(rb_Float(from))->value;
                f = HTOVF(f,ftmp);
                rb_str_buf_cat(res, (char*)&f, sizeof(float));
            }
            break;

          case 'E':            /* double precision float in VAX byte-order */
            while (len-- > 0) {
                double d;
                DOUBLE_CONVWITH(dtmp);

                from = NEXTFROM;
                d = RFLOAT(rb_Float(from))->value;
                d = HTOVD(d,dtmp);
                rb_str_buf_cat(res, (char*)&d, sizeof(double));
            }
            break;

          case 'd':            /* double precision float in native format */
          case 'D':            /* ditto */
            while (len-- > 0) {
                double d;

                from = NEXTFROM;
                d = RFLOAT(rb_Float(from))->value;
                rb_str_buf_cat(res, (char*)&d, sizeof(double));
            }
            break;

          case 'g':            /* single precision float in network byte-order */
            while (len-- > 0) {
                float f;
                FLOAT_CONVWITH(ftmp);

                from = NEXTFROM;
                f = RFLOAT(rb_Float(from))->value;
                f = HTONF(f,ftmp);
                rb_str_buf_cat(res, (char*)&f, sizeof(float));
            }
            break;

          case 'G':            /* double precision float in network byte-order */
            while (len-- > 0) {
                double d;
                DOUBLE_CONVWITH(dtmp);

                from = NEXTFROM;
                d = RFLOAT(rb_Float(from))->value;
                d = HTOND(d,dtmp);
                rb_str_buf_cat(res, (char*)&d, sizeof(double));
            }
            break;

          case 'x':            /* null byte */
          grow:
            while (len >= 10) {
                rb_str_buf_cat(res, nul10, 10);
                len -= 10;
            }
            rb_str_buf_cat(res, nul10, len);
            break;

          case 'X':            /* back up byte */
          shrink:
            plen = RSTRING(res)->len;
            if (plen < len)
                rb_raise(rb_eArgError, "X outside of string");
            RSTRING(res)->len = plen - len;
            RSTRING(res)->ptr[plen - len] = '\0';
            break;

          case '@':            /* null fill to absolute position */
            len -= RSTRING(res)->len;
            if (len > 0) goto grow;
            len = -len;
            if (len > 0) goto shrink;
            break;

          case '%':
            rb_raise(rb_eArgError, "%% is not supported");
            break;

          case 'U':            /* Unicode character */
            while (len-- > 0) {
                long l;
                char buf[8];
                int le;

                from = NEXTFROM;
                from = rb_to_int(from);
                l = NUM2INT(from);
                if (l < 0) {
                    rb_raise(rb_eRangeError, "pack(U): value out of range");
                }
                le = uv_to_utf8(buf, l);
                rb_str_buf_cat(res, (char*)buf, le);
            }
            break;

          case 'u':            /* uuencoded string */
          case 'm':            /* base64 encoded string */
            from = NEXTFROM;
            StringValue(from);
            ptr = RSTRING(from)->ptr;
            plen = RSTRING(from)->len;

            if (len <= 2)
                len = 45;
            else
                len = len / 3 * 3;
            while (plen > 0) {
                long todo;

                if (plen > len)
                    todo = len;
                else
                    todo = plen;
                encodes(res, ptr, todo, type);
                plen -= todo;
                ptr += todo;
            }
            break;

          case 'M':            /* quoted-printable encoded string */
            from = rb_obj_as_string(NEXTFROM);
            if (len <= 1)
                len = 72;
            qpencode(res, from, len);
            break;

          case 'P':            /* pointer to packed byte string */
            from = THISFROM;
            if (!NIL_P(from)) {
                StringValue(from);
                if (RSTRING(from)->len < len) {
                    rb_raise(rb_eArgError, "too short buffer for P(%ld for %ld)",
                             RSTRING(from)->len, len);
                }
            }
            len = 1;
            /* FALL THROUGH */
          case 'p':            /* pointer to string */
            while (len-- > 0) {
                char *t;
                from = NEXTFROM;
                if (NIL_P(from)) {
                    t = 0;
                }
                else {
                    t = StringValuePtr(from);
                }
                if (!associates) {
                    associates = rb_ary_new();
                }
                rb_ary_push(associates, from);
                rb_obj_taint(from);
                rb_str_buf_cat(res, (char*)&t, sizeof(char*));
            }
            break;

          case 'w':            /* BER compressed integer  */
            while (len-- > 0) {
                unsigned long ul;
                VALUE buf = rb_str_new(0, 0);
                char c, *bufs, *bufe;

                from = NEXTFROM;
                if (TYPE(from) == T_BIGNUM) {
                    VALUE big128 = rb_uint2big(128);
                    while (TYPE(from) == T_BIGNUM) {
                        from = rb_big_divmod(from, big128);
                        c = NUM2INT(RARRAY(from)->ptr[1]) | 0x80; /* mod */
                        rb_str_buf_cat(buf, &c, sizeof(char));
                        from = RARRAY(from)->ptr[0]; /* div */
                    }
                }

                {
                    long l = NUM2LONG(from);
                    if (l < 0) {
                        rb_raise(rb_eArgError, "can't compress negative numbers");
                    }
                    ul = l;
                }

                while (ul) {
                    c = ((ul & 0x7f) | 0x80);
                    rb_str_buf_cat(buf, &c, sizeof(char));
                    ul >>=  7;
                }

                if (RSTRING(buf)->len) {
                    bufs = RSTRING(buf)->ptr;
                    bufe = bufs + RSTRING(buf)->len - 1;
                    *bufs &= 0x7f; /* clear continue bit */
                    while (bufs < bufe) { /* reverse */
                        c = *bufs;
                        *bufs++ = *bufe;
                        *bufe-- = c;
                    }
                    rb_str_buf_cat(res, RSTRING(buf)->ptr, RSTRING(buf)->len);
                }
                else {
                    c = 0;
                    rb_str_buf_cat(res, &c, sizeof(char));
                }
            }
            break;

          default:
            break;
        }
    }

    if (associates) {
        rb_str_associate(res, associates);
    }
    OBJ_INFECT(res, fmt);
    return res;
}
            
permutation { |p| block } → array click to toggle source
permutation → enumerator
permutation(n) { |p| block } → array
permutation(n) → enumerator

When invoked with a block, yield all permutations of length n of the elements of ary, then return the array itself. If n is not specified, yield all permutations of all elements. The implementation makes no guarantees about the order in which the permutations are yielded.

When invoked without a block, return an enumerator object instead.

Examples:

a = [1, 2, 3]
a.permutation.to_a     #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(1).to_a  #=> [[1],[2],[3]]
a.permutation(2).to_a  #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]]
a.permutation(3).to_a  #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(0).to_a  #=> [[]] # one permutation of length 0
a.permutation(4).to_a  #=> []   # no permutations of length 4
 
               static VALUE
rb_ary_permutation(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE num;
    long r, n, i;

    n = RARRAY(ary)->len;                  /* Array length */
    RETURN_ENUMERATOR(ary, argc, argv);   /* Return enumerator if no block */
    rb_scan_args(argc, argv, "01", &num);
    r = NIL_P(num) ? n : NUM2LONG(num);   /* Permutation size from argument */

    if (r < 0 || n < r) { 
        /* no permutations: yield nothing */
    }
    else if (r == 0) { /* exactly one permutation: the zero-length array */
        rb_yield(rb_ary_new2(0));
    }
    else if (r == 1) { /* this is a special, easy case */
        for (i = 0; i < RARRAY(ary)->len; i++) {
            rb_yield(rb_ary_new3(1, RARRAY(ary)->ptr[i]));
        }
    }
    else {             /* this is the general case */
        volatile VALUE t0 = tmpbuf(n,sizeof(long));
        long *p = (long*)RSTRING(t0)->ptr;
        volatile VALUE t1 = tmpbuf(n,sizeof(int));
        int *used = (int*)RSTRING(t1)->ptr;
        VALUE ary0 = ary_make_shared(ary); /* private defensive copy of ary */

        for (i = 0; i < n; i++) used[i] = 0; /* initialize array */

        permute0(n, r, p, 0, used, ary0); /* compute and yield permutations */
        RB_GC_GUARD(t0);
        RB_GC_GUARD(t1);
    }
    return ary;
}
            
pop → obj or nil click to toggle source
pop(n) → array

Removes the last element from self and returns it, or nil if the array is empty.

If a number n is given, returns an array of the last n elements (or less) just like array.slice!(-n, n) does.

a = [ "a", "b", "c", "d" ]
a.pop     #=> "d"
a.pop(2)  #=> ["b", "c"]
a         #=> ["a"]
 
               static VALUE
rb_ary_pop_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE result;

    if (argc == 0) {
        return rb_ary_pop(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_shared_first(argc, argv, ary, Qtrue);
    RARRAY(ary)->len -= RARRAY(result)->len;
    return result;
}
            
product(other_ary, ...) click to toggle source

Returns an array of all combinations of elements from all arrays. The length of the returned array is the product of the length of ary and the argument arrays

[1,2,3].product([4,5])     # => [[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]]
[1,2].product([1,2])       # => [[1,1],[1,2],[2,1],[2,2]]
[1,2].product([3,4],[5,6]) # => [[1,3,5],[1,3,6],[1,4,5],[1,4,6],
                           #     [2,3,5],[2,3,6],[2,4,5],[2,4,6]]
[1,2].product()            # => [[1],[2]]
[1,2].product([])          # => []
 
               static VALUE
rb_ary_product(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    int n = argc+1;    /* How many arrays we're operating on */
    volatile VALUE t0 = tmpbuf(n, sizeof(VALUE));
    volatile VALUE t1 = tmpbuf(n, sizeof(int));
    VALUE *arrays = (VALUE*)RSTRING(t0)->ptr; /* The arrays we're computing the product of */
    int *counters = (int*)RSTRING(t1)->ptr; /* The current position in each one */
    VALUE result;      /* The array we'll be returning */
    long i,j;
    long resultlen = 1;

    RBASIC(t0)->klass = 0;
    RBASIC(t1)->klass = 0;

    /* initialize the arrays of arrays */
    arrays[0] = ary;
    for (i = 1; i < n; i++) arrays[i] = to_ary(argv[i-1]);
    
    /* initialize the counters for the arrays */
    for (i = 0; i < n; i++) counters[i] = 0;

    /* Compute the length of the result array; return [] if any is empty */
    for (i = 0; i < n; i++) {
        long k = RARRAY(arrays[i])->len, l = resultlen;
        if (k == 0) return rb_ary_new2(0);
        resultlen *= k;
        if (resultlen < k || resultlen < l || resultlen / k != l) {
            rb_raise(rb_eRangeError, "too big to product");
        }
    }

    /* Otherwise, allocate and fill in an array of results */
    result = rb_ary_new2(resultlen);
    for (i = 0; i < resultlen; i++) {
        int m;
        /* fill in one subarray */
        VALUE subarray = rb_ary_new2(n);
        for (j = 0; j < n; j++) {
            rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
        }

        /* put it on the result array */
        rb_ary_push(result, subarray);

        /*
         * Increment the last counter.  If it overflows, reset to 0
         * and increment the one before it.
         */
        m = n-1;
        counters[m]++;
        while (m > 0 && counters[m] == RARRAY(arrays[m])->len) {
            counters[m] = 0;
            m--;
            counters[m]++;
        }
    }

    return result;
}
            
push(obj, ... ) → array click to toggle source

Append—Pushes the given object(s) on to the end of this array. This expression returns the array itself, so several appends may be chained together.

a = [ "a", "b", "c" ]
a.push("d", "e", "f")  
        #=> ["a", "b", "c", "d", "e", "f"]
 
               static VALUE
rb_ary_push_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    while (argc--) {
        rb_ary_push(ary, *argv++);
    }
    return ary;
}
            
rassoc(key) → an_array or nil click to toggle source

Searches through the array whose elements are also arrays. Compares key with the second element of each contained array using ==. Returns the first contained array that matches. See also Array#assoc.

a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
a.rassoc("two")    #=> [2, "two"]
a.rassoc("four")   #=> nil
 
               VALUE
rb_ary_rassoc(ary, value)
    VALUE ary, value;
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY(ary)->len; ++i) {
        v = RARRAY(ary)->ptr[i];
        if (TYPE(v) == T_ARRAY &&
            RARRAY(v)->len > 1 &&
            rb_equal(RARRAY(v)->ptr[1], value))
            return v;
    }
    return Qnil;
}
            
reject {|item| block } → an_array click to toggle source

Returns a new array containing the items in self for which the block is not true.

 
               static VALUE
rb_ary_reject(ary)
    VALUE ary;
{
    RETURN_ENUMERATOR(ary, 0, 0);
    ary = rb_ary_dup(ary);
    rb_ary_reject_bang(ary);
    return ary;
}
            
reject! {|item| block } → array or nil click to toggle source

Equivalent to Array#delete_if, deleting elements from self for which the block evaluates to true, but returns nil if no changes were made. Also see Enumerable#reject.

 
               static VALUE
rb_ary_reject_bang(ary)
    VALUE ary;
{
    long i1, i2;

    RETURN_ENUMERATOR(ary, 0, 0);
    rb_ary_modify(ary);
    for (i1 = i2 = 0; i1 < RARRAY(ary)->len; i1++) {
        VALUE v = RARRAY(ary)->ptr[i1];
        if (RTEST(rb_yield(v))) continue;
        if (i1 != i2) {
            rb_ary_store(ary, i2, v);
        }
        i2++;
    }
    if (RARRAY(ary)->len == i2) return Qnil;
    if (i2 < RARRAY(ary)->len)
        RARRAY(ary)->len = i2;

    return ary;
}
            
replace(other_array) → array click to toggle source

Replaces the contents of self with the contents of other_array, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]
 
               static VALUE
rb_ary_replace(copy, orig)
    VALUE copy, orig;
{
    VALUE shared;

    rb_ary_modify(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;
    shared = ary_make_shared(orig);
    if (RARRAY(copy)->ptr && !FL_TEST(copy, ELTS_SHARED))
        free(RARRAY(copy)->ptr);
    RARRAY(copy)->ptr = RARRAY(orig)->ptr;
    RARRAY(copy)->len = RARRAY(orig)->len;
    RARRAY(copy)->aux.shared = shared;
    FL_SET(copy, ELTS_SHARED);

    return copy;
}
            
reverse → an_array click to toggle source

Returns a new array containing self’s elements in reverse order.

[ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
[ 1 ].reverse               #=> [1]
 
               static VALUE
rb_ary_reverse_m(ary)
    VALUE ary;
{
    return rb_ary_reverse(rb_ary_dup(ary));
}
            
reverse! → array click to toggle source

Reverses self in place.

a = [ "a", "b", "c" ]
a.reverse!       #=> ["c", "b", "a"]
a                #=> ["c", "b", "a"]
 
               static VALUE
rb_ary_reverse_bang(ary)
    VALUE ary;
{
    return rb_ary_reverse(ary);
}
            
reverse_each {|item| block } click to toggle source

Same as Array#each, but traverses self in reverse order.

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }

produces:

c b a
 
               static VALUE
rb_ary_reverse_each(ary)
    VALUE ary;
{
    long len;

    RETURN_ENUMERATOR(ary, 0, 0);
    len = RARRAY(ary)->len;
    while (len--) {
        rb_yield(RARRAY(ary)->ptr[len]);
        if (RARRAY(ary)->len < len) {
            len = RARRAY(ary)->len;
        }
    }
    return ary;
}
            
rindex(obj) → int or nil click to toggle source

Returns the index of the last object in array == to obj. If a block is given instead of an argument, returns first object for which block is true. Returns nil if no match is found.

a = [ "a", "b", "b", "b", "c" ]
a.rindex("b")        #=> 3
a.rindex("z")        #=> nil
a.rindex{|x|x=="b"}  #=> 3
 
               static VALUE
rb_ary_rindex(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE val;
    long i = RARRAY(ary)->len;

    if (argc == 0) {
        RETURN_ENUMERATOR(ary, 0, 0);
        while (i--) {
            if (RTEST(rb_yield(RARRAY(ary)->ptr[i])))
                return LONG2NUM(i);
            if (i > RARRAY(ary)->len) {
                i = RARRAY(ary)->len;
            }
        }
        return Qnil;
    }
    rb_scan_args(argc, argv, "01", &val);
    while (i--) {
        if (rb_equal(RARRAY(ary)->ptr[i], val))
            return LONG2NUM(i);
        if (i > RARRAY(ary)->len) {
            i = RARRAY(ary)->len;
        }
    }
    return Qnil;
}
            
select {|item| block } → an_array click to toggle source

Invokes the block passing in successive elements from array, returning an array containing those elements for which the block returns a true value (equivalent to Enumerable#select).

a = %w{ a b c d e f }
a.select {|v| v =~ /[aeiou]/}   #=> ["a", "e"]
 
               static VALUE
rb_ary_select(ary)
    VALUE ary;
{
    VALUE result;
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    result = rb_ary_new2(RARRAY(ary)->len);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        if (RTEST(rb_yield(RARRAY(ary)->ptr[i]))) {
            rb_ary_push(result, rb_ary_elt(ary, i));
        }
    }
    return result;
}
            
shift → obj or nil click to toggle source
shift(n) → array

Returns the first element of self and removes it (shifting all other elements down by one). Returns nil if the array is empty.

If a number n is given, returns an array of the first n elements (or less) just like array.slice!(0, n) does.

args = [ "-m", "-q", "filename" ]
args.shift     #=> "-m"
args           #=> ["-q", "filename"]

args = [ "-m", "-q", "filename" ]
args.shift(2)  #=> ["-m", "-q"]
args           #=> ["filename"]
 
               static VALUE
rb_ary_shift_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE result;
    long n;

    if (argc == 0) {
        return rb_ary_shift(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_shared_first(argc, argv, ary, Qfalse);
    n = RARRAY(result)->len;
    if (FL_TEST(ary, ELTS_SHARED)) {
        RARRAY(ary)->ptr += n;
        RARRAY(ary)->len -= n;
        }
    else {
        MEMMOVE(RARRAY(ary)->ptr, RARRAY(ary)->ptr+n, VALUE, RARRAY(ary)->len-n);
        RARRAY(ary)->len -= n;
    }

    return result;
}
            
shuffle → an_array click to toggle source

Returns a new array with elements of this array shuffled.

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle                 #=> [2, 3, 1]
 
               static VALUE
rb_ary_shuffle(VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_shuffle_bang(ary);
    return ary;
}
            
shuffle! → array or nil click to toggle source

Shuffles elements in self in place.

 
               static VALUE
rb_ary_shuffle_bang(ary)
    VALUE ary;
{
    long i = RARRAY(ary)->len;

    rb_ary_modify(ary);
    while (i) {
        long j = rb_genrand_real()*i;
        VALUE tmp = RARRAY(ary)->ptr[--i];
        RARRAY(ary)->ptr[i] = RARRAY(ary)->ptr[j];
        RARRAY(ary)->ptr[j] = tmp;
    }
    return ary;
}
            
size() click to toggle source
Alias for: length
slice(index) → obj or nil click to toggle source
slice(start, length) → an_array or nil
slice(range) → an_array or nil

Element Reference—Returns the element at index, or returns a subarray starting at start and continuing for length elements, or returns a subarray specified by range. Negative indices count backward from the end of the array (-1 is the last element). Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []
 
               VALUE
rb_ary_aref(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
        if (SYMBOL_P(argv[0])) {
            rb_raise(rb_eTypeError, "Symbol as array index");
        }
        beg = NUM2LONG(argv[0]);
        len = NUM2LONG(argv[1]);
        if (beg < 0) {
            beg += RARRAY(ary)->len;
        }
        return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
        rb_scan_args(argc, argv, "11", 0, 0);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
        return rb_ary_entry(ary, FIX2LONG(arg));
    }
    if (SYMBOL_P(arg)) {
        rb_raise(rb_eTypeError, "Symbol as array index");
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY(ary)->len, 0)) {
      case Qfalse:
        break;
      case Qnil:
        return Qnil;
      default:
        return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}
            
slice!(index) → obj or nil click to toggle source
slice!(start, length) → sub_array or nil
slice!(range) → sub_array or nil

Deletes the element(s) given by an index (optionally with a length) or by a range. Returns the deleted object, subarray, or nil if the index is out of range. Equivalent to:

def slice!(*args)
  result = self[*args]
  self[*args] = nil
  result
end

a = [ "a", "b", "c" ]
a.slice!(1)     #=> "b"
a               #=> ["a", "c"]
a.slice!(-1)    #=> "c"
a               #=> ["a"]
a.slice!(100)   #=> nil
a               #=> ["a"]
 
               static VALUE
rb_ary_slice_bang(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE arg1, arg2;
    long pos, len, orig_len;

    rb_ary_modify_check(ary);
    if (rb_scan_args(argc, argv, "11", &arg1, &arg2) == 2) {
        pos = NUM2LONG(arg1);
        len = NUM2LONG(arg2);
      delete_pos_len:
        if (len < 0) return Qnil;
        orig_len = RARRAY_LEN(ary);
        if (pos < 0) {
            pos += orig_len;
            if (pos < 0) return Qnil;
        }
        else if (orig_len < pos) return Qnil;
        if (orig_len < pos + len) {
            len = orig_len - pos;
        }
        if (len == 0) return rb_ary_new2(0);
        arg2 = rb_ary_new4(len, RARRAY_PTR(ary)+pos);
        RBASIC(arg2)->klass = rb_obj_class(ary);
        rb_ary_splice(ary, pos, len, Qnil);    /* Qundef in 1.9 */
        return arg2;
    }

    if (!FIXNUM_P(arg1)) {
        switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
          case Qtrue:
            /* valid range */
            goto delete_pos_len;
          case Qnil:
            /* invalid range */
            return Qnil;
          default:
            /* not a range */
            break;
        }
    }

    return rb_ary_delete_at(ary, NUM2LONG(arg1));
}
            
sort → an_array click to toggle source
sort {| a,b | block } → an_array

Returns a new array created by sorting self. Comparisons for the sort will be done using the <=> operator or using an optional code block. The block implements a comparison between a and b, returning -1, 0, or +1. See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]
 
               VALUE
rb_ary_sort(ary)
    VALUE ary;
{
    ary = rb_ary_dup(ary);
    rb_ary_sort_bang(ary);
    return ary;
}
            
sort! → array click to toggle source
sort! {| a,b | block } → array

Sorts self. Comparisons for the sort will be done using the <=> operator or using an optional code block. The block implements a comparison between a and b, returning -1, 0, or +1. See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]
 
               VALUE
rb_ary_sort_bang(ary)
    VALUE ary;
{
    rb_ary_modify(ary);
    if (RARRAY(ary)->len > 1) {
        FL_SET(ary, ARY_TMPLOCK);      /* prohibit modification during sort */
        rb_ensure(sort_internal, ary, sort_unlock, ary);
    }
    return ary;
}
            
take(n) => array click to toggle source

Returns first n elements from ary.

a = [1, 2, 3, 4, 5, 0]
a.take(3)             # => [1, 2, 3]
 
               static VALUE
rb_ary_take(obj, n)
    VALUE obj;
    VALUE n;
{
    long len = NUM2LONG(n);
    if (len < 0) {
        rb_raise(rb_eArgError, "attempt to take negative size");
    }

    return rb_ary_subseq(obj, 0, len);
}
            
take_while {|arr| block } => array click to toggle source

Passes elements to the block until the block returns nil or false, then stops iterating and returns an array of all prior elements.

a = [1, 2, 3, 4, 5, 0]
a.take_while {|i| i < 3 }   # => [1, 2]
 
               static VALUE
rb_ary_take_while(ary)
    VALUE ary;
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY(ary)->len; i++) {
        if (!RTEST(rb_yield(RARRAY(ary)->ptr[i]))) break;
    }
    return rb_ary_take(ary, LONG2FIX(i));
}
            
to_a → array click to toggle source

Returns self. If called on a subclass of Array, converts the receiver to an Array object.

 
               static VALUE
rb_ary_to_a(ary)
    VALUE ary;
{
    if (rb_obj_class(ary) != rb_cArray) {
        VALUE dup = rb_ary_new2(RARRAY(ary)->len);
        rb_ary_replace(dup, ary);
        return dup;
    }
    return ary;
}
            
to_ary → array click to toggle source

Returns self.

 
               static VALUE
rb_ary_to_ary_m(ary)
    VALUE ary;
{
    return ary;
}
            
to_s → string click to toggle source

Returns self.join.

[ "a", "e", "i", "o" ].to_s   #=> "aeio"
 
               VALUE
rb_ary_to_s(ary)
    VALUE ary;
{
    if (RARRAY(ary)->len == 0) return rb_str_new(0, 0);
    
    return rb_ary_join(ary, rb_output_fs);
}
            
transpose → an_array click to toggle source

Assumes that self is an array of arrays and transposes the rows and columns.

a = [[1,2], [3,4], [5,6]]
a.transpose   #=> [[1, 3, 5], [2, 4, 6]]
 
               static VALUE
rb_ary_transpose(ary)
    VALUE ary;
{
    long elen = -1, alen, i, j;
    VALUE tmp, result = 0;

    alen = RARRAY(ary)->len;
    if (alen == 0) return rb_ary_dup(ary);
    for (i=0; i<alen; i++) {
        tmp = to_ary(rb_ary_elt(ary, i));
        if (elen < 0) {                /* first element */
            elen = RARRAY(tmp)->len;
            result = rb_ary_new2(elen);
            for (j=0; j<elen; j++) {
                rb_ary_store(result, j, rb_ary_new2(alen));
            }
        }
        else if (elen != RARRAY(tmp)->len) {
            rb_raise(rb_eIndexError, "element size differs (%d should be %d)",
                     RARRAY(tmp)->len, elen);
        }
        for (j=0; j<elen; j++) {
            rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
        }
    }
    return result;
}
            
uniq → an_array click to toggle source

Returns a new array by removing duplicate values in self.

a = [ "a", "a", "b", "b", "c" ]
a.uniq   #=> ["a", "b", "c"]
 
               static VALUE
rb_ary_uniq(ary)
    VALUE ary;
{
    ary = rb_ary_dup(ary);
    rb_ary_uniq_bang(ary);
    return ary;
}
            
uniq! → array or nil click to toggle source

Removes duplicate elements from self. Returns nil if no changes are made (that is, no duplicates are found).

a = [ "a", "a", "b", "b", "c" ]
a.uniq!   #=> ["a", "b", "c"]
b = [ "a", "b", "c" ]
b.uniq!   #=> nil
 
               static VALUE
rb_ary_uniq_bang(ary)
    VALUE ary;
{
    VALUE hash, v, vv;
    long i, j;

    hash = ary_make_hash(ary, 0);

    if (RARRAY(ary)->len == RHASH(hash)->tbl->num_entries) {
        return Qnil;
    }
    for (i=j=0; i<RARRAY(ary)->len; i++) {
        v = vv = rb_ary_elt(ary, i);
        if (st_delete(RHASH(hash)->tbl, (st_data_t*)&vv, 0)) {
            rb_ary_store(ary, j++, v);
        }
    }
    RARRAY(ary)->len = j;

    return ary;
}
            
unshift(obj, ...) → array click to toggle source

Prepends objects to the front of array. other elements up one.

a = [ "b", "c", "d" ]
a.unshift("a")   #=> ["a", "b", "c", "d"]
a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]
 
               static VALUE
rb_ary_unshift_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    long len = RARRAY(ary)->len;

    if (argc == 0) return ary;

    /* make rooms by setting the last item */
    rb_ary_store(ary, len + argc - 1, Qnil);

    /* sliding items */
    MEMMOVE(RARRAY(ary)->ptr + argc, RARRAY(ary)->ptr, VALUE, len);
    MEMCPY(RARRAY(ary)->ptr, argv, VALUE, argc);
    
    return ary;
}
            
values_at(selector,... ) → an_array click to toggle source

Returns an array containing the elements in self corresponding to the given selector(s). The selectors may be either integer indices or ranges. See also Array#select.

a = %w{ a b c d e f }
a.values_at(1, 3, 5)
a.values_at(1, 3, 5, 7)
a.values_at(-1, -3, -5, -7)
a.values_at(1..3, 2...5)
 
               static VALUE
rb_ary_values_at(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    return rb_values_at(ary, RARRAY(ary)->len, argc, argv, rb_ary_entry);
}
            
zip(arg, ...) → an_array click to toggle source
zip(arg, ...) {| arr | block } → nil

Converts any arguments to arrays, then merges elements of self with corresponding elements from each argument. This generates a sequence of self.size n-element arrays, where n is one more that the count of arguments. If the size of any argument is less than enumObj.size, nil values are supplied. If a block given, it is invoked for each output array, otherwise an array of arrays is returned.

a = [ 4, 5, 6 ]
b = [ 7, 8, 9 ]

[1,2,3].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
[1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8]]
a.zip([1,2],[8])       #=> [[4,1,8], [5,2,nil], [6,nil,nil]]
 
               static VALUE
rb_ary_zip(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    int i, j;
    long len;
    VALUE result;

    for (i=0; i<argc; i++) {
        argv[i] = to_ary(argv[i]);
    }
    if (rb_block_given_p()) {
        for (i=0; i<RARRAY(ary)->len; i++) {
            VALUE tmp = rb_ary_new2(argc+1);

            rb_ary_push(tmp, rb_ary_elt(ary, i));
            for (j=0; j<argc; j++) {
                rb_ary_push(tmp, rb_ary_elt(argv[j], i));
            }
            rb_yield(tmp);
        }
        return Qnil;
    }
    len = RARRAY(ary)->len;
    result = rb_ary_new2(len);
    for (i=0; i<len; i++) {
        VALUE tmp = rb_ary_new2(argc+1);

        rb_ary_push(tmp, rb_ary_elt(ary, i));
        for (j=0; j<argc; j++) {
            rb_ary_push(tmp, rb_ary_elt(argv[j], i));
        }
        rb_ary_push(result, tmp);
    }
    return result;
}
            
array | other_array → an_array click to toggle source

Set Union—Returns a new array by joining this array with other_array, removing duplicates.

[ "a", "b", "c" ] | [ "c", "d", "a" ]
       #=> [ "a", "b", "c", "d" ]
 
               static VALUE
rb_ary_or(ary1, ary2)
    VALUE ary1, ary2;
{
    VALUE hash, ary3;
    VALUE v, vv;
    long i;

    ary2 = to_ary(ary2);
    ary3 = rb_ary_new2(RARRAY(ary1)->len+RARRAY(ary2)->len);
    hash = ary_make_hash(ary1, ary2);

    for (i=0; i<RARRAY(ary1)->len; i++) {
        v = vv = rb_ary_elt(ary1, i);
        if (st_delete(RHASH(hash)->tbl, (st_data_t*)&vv, 0)) {
            rb_ary_push(ary3, v);
        }
    }
    for (i=0; i<RARRAY(ary2)->len; i++) {
        v = vv = rb_ary_elt(ary2, i);
        if (st_delete(RHASH(hash)->tbl, (st_data_t*)&vv, 0)) {
            rb_ary_push(ary3, v);
        }
    }
    return ary3;
}
            

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