From: transfire@...
Date: 2014-11-02T17:19:23+00:00
Subject: [ruby-core:66051] [ruby-trunk - Feature #7793] New methods on Hash

Issue #7793 has been updated by Thomas Sawyer.


I can't help but mention it, because it gave me a chuckle....

I like `rekey` and `revalue` from #4, because they make sense semantically, don't confuse the idea of `map` returning an array, and they are *concise*. Concision is always a big plus. However `graph` and `mash` don't really convey much in their names (`mash` is combination of "map" and "hash" btw), so I've always been rather ho-hum about those, but never could come up with a better, yet still concise, alternative.

Options #2 and #5 are nice for their consistency --the use of `_keys`, `_values` and `_pairs`-- But they lack for concision (especially #5) which sucks, and #2 has the map name issue as mentioned.

So I tried a combination of both ideas using `re-` as the prefix to the three suffixes and got:

* `rekey`
* `revalue`
* `repair`

At which point the giggles kicked in :-)



----------------------------------------
Feature #7793: New methods on Hash
https://bugs.ruby-lang.org/issues/7793#change-49772

* Author: Dominic Sisneros
* Status: Assigned
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: core
* Target version: next minor
----------------------------------------
It would be nice to have the following methods added to hash

~~~ruby
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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