YAML::DBM
class YAML::DBM
YAML + DBM = YDBM
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 lib/yaml/dbm.rb, line 28 def []( key ) fetch( key ) end
Deletes value from database associated with key
.
Returns value or nil
.
# File lib/yaml/dbm.rb, line 101 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 lib/yaml/dbm.rb, line 116 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 lib/yaml/dbm.rb, line 139 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 lib/yaml/dbm.rb, line 150 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 lib/yaml/dbm.rb, line 55 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 lib/yaml/dbm.rb, line 167 def has_value?( val ) each_value { |v| return true if v == val } return false 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 lib/yaml/dbm.rb, line 180 def invert h = {} keys.each { |k| h[ self.fetch( k ) ] = k } h end
Returns the key for the specified value.
# File lib/yaml/dbm.rb, line 83 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 lib/yaml/dbm.rb, line 128 def reject hsh = self.to_hash hsh.reject { |k,v| yield k, v } end
Replaces the contents of the database with the contents of the specified object. Takes any object which implements the #each_pair method, including Hash and DBM objects-
# File lib/yaml/dbm.rb, line 192 def replace( hsh ) clear update( hsh ) 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 lib/yaml/dbm.rb, line 218 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 lib/yaml/dbm.rb, line 204 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 lib/yaml/dbm.rb, line 233 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 lib/yaml/dbm.rb, line 258 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 lib/yaml/dbm.rb, line 270 def to_hash h = {} keys.each { |k| h[ k ] = self.fetch( k ) } h end
Updates the database with multiple values from the specified object. Takes any object which implements the #each_pair method, including Hash and DBM objects-
Returns self
-
# File lib/yaml/dbm.rb, line 246 def update( hsh ) hsh.each_pair do |k,v| self.store( k, v ) end self end
Returns an array of values from the database.
# File lib/yaml/dbm.rb, line 159 def values super.collect { |v| YAML.load( v ) } end
Returns an array containing the values associated with the given keys.
# File lib/yaml/dbm.rb, line 91 def values_at( *keys ) keys.collect { |k| fetch( k ) } end
Ruby Core © 1993–2017 Yukihiro Matsumoto
Licensed under the Ruby License.
Ruby Standard Library © contributors
Licensed under their own licenses.