class YAML::DBM
YAML::DBM
provides the same interface as ::DBM.
However, while DBM
only allows strings for both keys and values, this library allows one to use most Ruby objects for values by first converting them to YAML
. Keys must be strings.
Conversion to and from YAML
is performed automatically.
See the documentation for ::DBM and ::YAML
for more information.
Public Instance Methods
Return value associated with key
from database.
Returns nil
if there is no such key
.
See fetch
for more information.
# File yaml/dbm.rb, line 29 def []( key ) fetch( key ) end
Deletes value from database associated with key
.
Returns value or nil
.
# File yaml/dbm.rb, line 102 def delete( key ) v = super( key ) if String === v v = YAML.load( v ) end v end
Calls the given block once for each key
, value
pair in the database. Deletes all entries for which the block returns true.
Returns self
.
# File yaml/dbm.rb, line 117 def delete_if # :yields: [key, value] del_keys = keys.dup del_keys.delete_if { |k| yield( k, fetch( k ) ) == false } del_keys.each { |k| delete( k ) } self end
Calls the given block once for each key
, value
pair in the database.
Returns self
.
# File yaml/dbm.rb, line 140 def each_pair # :yields: [key, value] keys.each { |k| yield k, fetch( k ) } self end
Calls the given block for each value in database.
Returns self
.
# File yaml/dbm.rb, line 151 def each_value # :yields: value super { |v| yield YAML.load( v ) } self end
Return value associated with key
.
If there is no value for key
and no block is given, returns ifnone
.
Otherwise, calls block passing in the given key
.
See ::DBM#fetch for more information.
# File yaml/dbm.rb, line 56 def fetch( keystr, ifnone = nil ) begin val = super( keystr ) return YAML.load( val ) if String === val rescue IndexError end if block_given? yield keystr else ifnone end end
Returns true if specified value
is found in the database.
# File yaml/dbm.rb, line 168 def has_value?( val ) each_value { |v| return true if v == val } return false end
Deprecated, used YAML::DBM#key
instead.
Note: YAML::DBM#index
makes warning from internal of ::DBM#index. It says ‘DBM#index is deprecated; use DBM#key
’, but DBM#key
behaves not same as DBM#index
.
# File yaml/dbm.rb, line 76 def index( keystr ) super( keystr.to_yaml ) end
Returns a Hash (not a DBM
database) created by using each value in the database as a key, with the corresponding key as its value.
Note that all values in the hash will be Strings, but the keys will be actual objects.
# File yaml/dbm.rb, line 181 def invert h = {} keys.each { |k| h[ self.fetch( k ) ] = k } h end
Returns the key for the specified value.
# File yaml/dbm.rb, line 84 def key( keystr ) invert[keystr] end
Converts the contents of the database to an in-memory Hash, then calls Hash#reject with the specified code block, returning a new Hash.
# File yaml/dbm.rb, line 129 def reject hsh = self.to_hash hsh.reject { |k,v| yield k, v } end
If a block is provided, returns a new array containing [key, value] pairs for which the block returns true.
Otherwise, same as values_at
# File yaml/dbm.rb, line 219 def select( *keys ) if block_given? self.keys.collect { |k| v = self[k]; [k, v] if yield k, v }.compact else values_at( *keys ) end end
Removes a [key, value] pair from the database, and returns it. If the database is empty, returns nil
.
The order in which values are removed/returned is not guaranteed.
# File yaml/dbm.rb, line 205 def shift a = super a[1] = YAML.load( a[1] ) if a a end
Stores value
in database with key
as the index. value
is converted to YAML
before being stored.
Returns value
# File yaml/dbm.rb, line 234 def store( key, val ) super( key, val.to_yaml ) val end
Converts the contents of the database to an array of [key, value] arrays, and returns it.
# File yaml/dbm.rb, line 259 def to_a a = [] keys.each { |k| a.push [ k, self.fetch( k ) ] } a end
Converts the contents of the database to an in-memory Hash object, and returns it.
# File yaml/dbm.rb, line 271 def to_hash h = {} keys.each { |k| h[ k ] = self.fetch( k ) } h end
Returns an array of values from the database.
# File yaml/dbm.rb, line 160 def values super.collect { |v| YAML.load( v ) } end
Returns an array containing the values associated with the given keys.
# File yaml/dbm.rb, line 92 def values_at( *keys ) keys.collect { |k| fetch( k ) } end