From: Martin DeMello <martindemello@...>
Date: 2006-08-07T06:06:10+09:00
Subject: Re: Iterating over an array n element at a time

On 8/7/06, Marcelo Alvim <malvim@gmail.com> wrote:
> > Just a tiny little trap you fell into, look at this
> >  [1,2,3].each_slice(2){|s| p s}
> > NoMethodError: undefined method `each_slice' for [1, 2, 3]:Array
> >        from (irb):1
> >
> > but
> >
> > irb(main):003:0> require 'enumerator'
> > => true
> > irb(main):004:0>  [1,2,3].each_slice(2){|s| p s}
> > [1, 2]
> > [3]
> >
> > I have fallen into that one more than once and I still  will, it is a little
> > bit unclear why  Enumerable is not in the core while it is in the core doc.
> > But well just a minor hickup.
>
> Oh, I see! Thanks for the pointer.
>
> I thought Array mixed that in, so it should be defined for it. But
> then again, I'm still getting used to modules, mixins and such. Been
> too long in a Java-only world...

Array does mix Enumerable in. However, the core Enumerable module
doesn't include each_slice; that is provided by the 'enumerator'
library, which reopens Enumerable and adds some methods to it. Note
that enumerator is in the standard lib rather than in the core.

http://www.ruby-doc.org/stdlib/libdoc/enumerator/rdoc/index.html

martin