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 29 def []( key ) fetch( key ) end
Deletes value from database associated with key
.
Returns value or nil
.
DBM#delete
# File lib/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 lib/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 lib/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
.
DBM#each_value
# File lib/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.
DBM#fetch
# File lib/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 lib/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 lib/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 lib/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 lib/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 lib/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 lib/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.
DBM#shift
# File lib/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
DBM#store
# File lib/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 lib/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 lib/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.
DBM#values
# File lib/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 lib/yaml/dbm.rb, line 92 def values_at( *keys ) keys.collect { |k| fetch( k ) } end