Advance ruby hash

ruby hash in better way

> [1,2,3].map{ |i| i+1 }
  => [2, 3, 4]
  _______________________________________________________________
   > { "x" => 1, "y" => 2, "z" => 3 }.map{ |k,v| k.to_sym => v }
  SyntaxError: (irb):2: syntax error, unexpected tASSOC, expecting '}'

  { "x" => 1, "y" => 2, "z" => 3 }.map{ |k,v| k.to_sym => v }
  from /home/smeagol/.rvm/rubies/ruby-1.9.3-p429/bin/irb:16:in `<main>'
____________________________________________________________________________________
> { "x" => 1, "y" => 2, "z" => 3 }.map{ |k,v| { k.to_sym => v } }
  => [{:x=>1}, {:y=>2}, {:z=>3}]
  ______________________________________________________________________________________
  > { "x" => 1, "y" => 2, "z" => 3 }.\
  > inject({}){ |hash, (k, v)| hash.merge( k.to_sym => v )  }
  => {:x=>1, :y=>2, :z=>3}
  > # if you prefer big-data parlance, the preferred term is reduce, not inject.
  > # Either way, Ruby doesn't care - they do the same thing.
  > { "x" => 1, "y" => 2, "z" => 3 }.\
  > reduce({}){ |hash, (k, v)| hash.merge( k.to_sym => v )  }
  => {:x=>1, :y=>2, :z=>3}
  _________________________________________________________________________________________
 
 class Hash
    def hmap(&block)
      self.inject({}){ |hash,(k,v)| hash.merge( block.call(k,v) ) }
    end
  end

  x = { "x" => 1, "y" => 2 }
  x.hmap{ |k,v| { k.to_sym => v.to_s  } }
  => {:x => "1", :y => "2"}

http://www.korenlc.com/nested-arrays-hashes-loops-in-ruby/