[ruby-core:68941] [Ruby trunk - Feature #11076] Enumerable method count_by

Issue #11076 has been updated by Harald B=C3=B6ttiger.


I am sorry but I am not sure to properly format this, but the documentation=
 would be like:

    Syntax:
      group_by { |obj| block } =E2=86=92 a_hash
      group_by =E2=86=92 an_enumerator
=20=20=20=20
    Description:
      Groups the collection by result of the block. Returns a hash where th=
e keys are the evaluated result from the block and the values are the numbe=
r of the elements in the collection that correspond to the key.
=20=20=20=20
      If no block is given an enumerator is returned.
=20=20=20=20
    Examples:
      ['a','a','a','b','c'].group_by { |x| x } #=3D> {'a'=3D>3, 'b'=3D>1, '=
c'=3D>1}
      (1..7).group_by { |i| i%3 }   #=3D> {0=3D>2, 1=3D>3, 2=3D>2}


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Feature #11076: Enumerable method count_by
https://bugs.ruby-lang.org/issues/11076#change-52204

* Author: Harald B=C3=B6ttiger
* Status: Open
* Priority: Low
* Assignee:=20
----------------------------------------
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 =3D ['aa', 'aA', 'bb', 'cc']
p array.count_by(&:downcase) #=3D> {'aa'=3D>2,'bb'=3D>1,'cc'=3D>1}
~~~



--=20
https://bugs.ruby-lang.org/