From: Alder Green <alder.green@...>
Date: 2006-05-12T00:10:04+09:00
Subject: Re: each with arguments

On 5/11/06, Mike Stok <mike@stok.ca> wrote:
>
> On 11-May-06, at 10:53 AM, Charles Churchill wrote:
>
> > I've found myself writing the following code to address needs I have
> > processing formatted text files, but is this possible some other and I
> > am going through foolish gyrations here...
> >
> > Here is the code:
> >
> >  class Array
> >     alias :orig_each :each
> >     def each(cnt = 1, &blk)
> >       if cnt == 1
> >          orig_each { |x| blk.call(x) }
> >       else
> >          0.step(self.size - 1,cnt) do |i|
> >             yield(self.slice(i,cnt))
> >          end
> >       end
> >    end
> >  end
> >
> > so I can do things like this
> >
> > arr = [ key, value, value, key, value, value, key, value, value, ... ]
> > arr.each(3) do |key,val1,val2|
> >    #manipulate them as I see fit
> > end
> >
> > Thanks for any help you can give!
>
> Have you looked at Enumerable#each_slice which is included in Array?
>
> ratdog:~ mike$ ri Enumerable#each_slice
> -------------------------------------------------- Enumerable#each_slice
>      e.each_slice(n) {...}
> ------------------------------------------------------------------------
>      Iterates the given block for each slice of <n> elements.
>
>      e.g.:
>
>          (1..10).each_slice(3) {|a| p a}
>          # outputs below
>          [1, 2, 3]
>          [4, 5, 6]
>          [7, 8, 9]
>          [10]
>
> Mike
>
> --
>
> Mike Stok <mike@stok.ca>
> http://www.stok.ca/~mike/
>
> The "`Stok' disclaimers" apply.
>
>

each_slice doesn't wfm if I don't require 'enumerator' first:

irb(main):001:0> (1..10).each_slice(3) {|a| p a}
(1..10).each_slice(3) {|a| p a}
NoMethodError: undefined method `each_slice' for 1..10:Range
	from (irb):1

irb(main):002:0> require 'enumerator'
require 'enumerator'
true

irb(main):003:0> (1..10).each_slice(3) {|a| p a}
(1..10).each_slice(3) {|a| p a}
[1, 2, 3]
[4, 5, 6]
[7, 8, 9]
[10]
nil