Sha256: fa2c4f82e1aa4f016cd69127898b9ebd3b1cdbbcf722e94e475f2f1c446caa68
Contents?: true
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Versions: 6
Compression:
Stored size: 1.9 KB
Contents
require 'facets/symbol/to_proc'
require 'facets/na'
class Hash
# Rekey a hash, ...
#
# rekey()
# rekey(from_key => to_key, ...)
# rekey{|from_key| to_key}
#
# If a key map is given, then the first key is changed to the second key.
#
# foo = { :a=>1, :b=>2 }
# foo.rekey(:a=>'a') #=> { 'a'=>1, :b=>2 }
# foo.rekey(:b=>:x) #=> { :a =>1, :x=>2 }
# foo.rekey('foo'=>'bar') #=> { :a =>1, :b=>2 }
#
# If a block is given, converts all keys in the Hash accroding to the
# given block procedure. If the block returns +NA+ for a given key,
# then that key will be left intact.
#
# foo = { :name=>'Gavin', :wife=>:Lisa }
# foo.rekey{ |k| k.to_s } #=> { "name"=>"Gavin", "wife"=>:Lisa }
# foo #=> { :name =>"Gavin", :wife=>:Lisa }
#
# If no key map or block is given, then all keys are converted
# to Symbols.
#
# Note that if both a +key_map+ and a block are given, the +key_map+ is
# applied first then the block.
#
# CREDIT: Trans, Gavin Kistner
def rekey(key_map=nil, &block)
if !(key_map or block)
block = lambda{|k| k.to_sym}
end
key_map ||= {}
hash = {}
(keys - key_map.keys).each do |key|
hash[key] = self[key]
end
key_map.each do |from, to|
hash[to] = self[from] if key?(from)
end
hash2 = {}
if block
hash.each do |k, v|
nk = block[k]
nk = (NA == nk ? k : nk)
hash2[nk] = v
end
else
hash2 = hash
end
hash2
end
# Synonym for Hash#rekey, but modifies the receiver in place (and returns it).
#
# foo = { :name=>'Gavin', :wife=>:Lisa }
# foo.rekey!{ |k| k.to_s } #=> { "name"=>"Gavin", "wife"=>:Lisa }
# foo #=> { "name"=>"Gavin", "wife"=>:Lisa }
#
# CREDIT: Trans, Gavin Kistner
def rekey!(key_map=nil, &block)
replace(rekey(key_map, &block))
end
end
Version data entries
6 entries across 5 versions & 1 rubygems