From: Robert Klemme <bob.news@...>
Date: 2005-07-08T19:20:48+09:00
Subject: Re: accessing index inside map

Pe�a, Botp wrote:
> nobuyoshi nakada [mailto:nobuyoshi.nakada@ge.com] wrote:
>
> #> i'd like to double the element values except those loc on
> #the 2nd and 5th
> #> indices eg.
> #
> #$ ruby -renumerator -e 'p
> #(1..6).enum_for(:each_with_index).map{|x,i|[2,5].include?(i) ?
> #x : x*2}'
> #[2, 4, 3, 8, 10, 6]
>
> Hi Nobu,
>
> Wow, cool. But my brain is very tiny compared to other rubyist brains.
>
> i was hoping for something straight like,
>
>> [1,2,3,4,5,6].map{|x,i|[2,5].include?(i) ? x : x*2}
> =>[2, 4, 3, 8, 10, 6]
>
> Maybe you can hack one for dumb rubyists like me.

Err, are you kidding?  Enumerator isn't really that difficult - and you
don't need to modify Hash or other classes.  It's a simple wrapper
delegating each to each_with_index.  That simple.

Regards

    robert