2010/12/16 Run Paint Run Run <runrun / runpaint.org>:

> We currently have #chunk, #group_by--so to some extent #partition--and
> #slice_before for segregating an Enumerable into an Enumerable of
> Enumerables. I understand their difference on paper, but still need to
> experiment with them in IRB before use. This proposal would add two
> more methods to this list--#categorize and matz's alternative--for
> what appear to be increasingly specialised uses. I'm unconvinced.

#chunk and #slice_before collects adjasent elements in enumerable.
#group_by and #categorize collects elements from all elements in enumerable.

#categorize is more general than #group_by.
It can specify hash values.
-- 
Tanaka Akira