[ruby-core:88373] [Ruby trunk Feature#11076] Enumerable method count_by

From: knu@...
Date: 2018-08-09 07:58:03 UTC
List: ruby-core #88373
Issue #11076 has been updated by knu (Akinori MUSHA).


In today's developer meeting, Matz understood the need for the feature but didn't like the name.  One point he made was that existing pairs like sort/sort_by and max/max_by share their features, count_by() might not go well with count().

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Feature #11076: Enumerable method count_by
https://bugs.ruby-lang.org/issues/11076#change-73413

* Author: haraldb (Harald B旦ttiger)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
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I very often use `Hash[array.group_by{|x|x}.map{|x,y|[x,y.size]}]`.

Would be nice with to have a method called `count_by`:

~~~ruby
array = ['aa', 'aA', 'bb', 'cc']
p array.count_by(&:downcase) #=> {'aa'=>2,'bb'=>1,'cc'=>1}
~~~



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