From: ahoward <ahoward@...>
Date: 2003-05-30T07:25:30+09:00
Subject: Re: Iteration - last detection

On Fri, 30 May 2003 dblack@superlink.net wrote:

> Let Ruby do more of the work for you :-)
>
>   module Enumerable
>     def each_with_last
>       each_with_index {|e,i| yield(e, i == size-1)}
>     end
>   end

this won't work for *anything* Enumerable though - though it works for Array
and Hash.

  "The Enumerable mixin provides collection classes with several traversal and
  searching methods, and with the ability to sort. The class must provide a
  method each, which yields successive members of the collection. If
  Enumerable#max , #min, or #sort is used, the objects in the collection must
  also implement a meaningful <=> operator, as these methods rely on an ordering
  between members of the collection."

so you may or may *not* have a size method.

> (Hmmm... could this be the non-superfluous use of Enumerable#each_with_index
> (as opposed to just Array#ewi) that I've been looking for for 2.5 years? :-)

you don't like it?  i use it all the time!  ;-)

-a
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  | NOAA Forecast Systems Laboratory
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