From: "dsisnero (Dominic Sisneros)" <dsisnero@...>
Date: 2013-02-07T05:02:05+09:00
Subject: [ruby-core:51945] [ruby-trunk - Feature #7793] New methods on Hash


Issue #7793 has been updated by dsisnero (Dominic Sisneros).


This should be re-opened.  It is not for all enumerables but only for hash.

map_v and map_k are very useful

map_kv is similar to h.mash and others and could be eliminated by those other bugs but the other functions aren't and are specifically for hashes and thus this should be re-opened



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Feature #7793: New methods on Hash
https://bugs.ruby-lang.org/issues/7793#change-35944

Author: dsisnero (Dominic Sisneros)
Status: Closed
Priority: Normal
Assignee: 
Category: 
Target version: 


It would be nice to have the following methods added to hash

h = { name: 'dominic', request: 'add the following methods', :why => 'convenience'}

h.map_v{|v| v.upcase} 
   {:name=>"DOMINIC", :request=>"ADD THE FOLLOWING METHODS", :why=>"CONVENIENCE"}

h.map_k{|k| k.to_s}
   { "name"=> 'dominic', "request"=>"add the following methods', "why" => "convenience"}

h.map_kv{|k,v| [k.to_s, v.upcase]}
   { "name"=>"DOMINIC", "request"=>"ADD THE FOLLOWING METHODS", "why"=>"CONVENIENCE"}


class Hash

  def map_v
    reduce({}) do |result, array|
      k,v = array
      new_val = yield v
      result.merge( k => new_val)
    end
  end

  def map_k
    reduce({}) do |result, array|
      k,v = array
      new_k = yield k
      result.merge(new_k => v)
    end
  end

  def map_kv
    reduce({}) do |result, array|
      new_k,new_v = yield array
      result.merge(new_k => new_v)
    end
  end

end


-- 
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