Class: Hash

Inherits:
Object
  • Object
show all
Defined in:
lib/indexer/core_ext/hash/to_h.rb,
lib/indexer/core_ext/hash/rekey.rb

Instance Method Summary collapse

Instance Method Details

#rekey(key_map = nil, &block) ⇒ Object

Rekey a hash:

rekey() rekey(from_key => to_key, ...) rekey{|from_key| to_key} rekey{|from_key, value| 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



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# File 'lib/indexer/core_ext/hash/rekey.rb', line 35

def rekey(key_map=nil, &block)
  if !(key_map or block)
    block = lambda{|k| k.to_sym}
  end

  key_map ||= {} 

  hash = dup.replace({})  # to keep default_proc

  (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

  if block
    hash2 = dup.replace({})
    case block.arity
    when 2  # TODO: is this condition needed?
      hash.each do |k, v|
        nk = block.call(k,v)
        nk = (nk ? nk : k)
        hash2[nk] = v
      end
    else
      hash.each do |k, v|
        nk = block.call(k)
        nk = (nk ? nk : k)
        hash2[nk] = v
      end
    end
  else
    hash2 = hash
  end

  hash2
end

#rekey!(key_map = nil, &block) ⇒ Object

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



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# File 'lib/indexer/core_ext/hash/rekey.rb', line 83

def rekey!(key_map=nil, &block)
  replace(rekey(key_map, &block))
end

#to_h ⇒ Object 



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# File 'lib/indexer/core_ext/hash/to_h.rb', line 2

def to_h; self; end