From: Robert Klemme <bob.news@...>
Date: 2004-07-07T00:17:43+09:00
Subject: Re: Array::index and rindex operator


"David A. Black" <dblack@wobblini.net> schrieb im Newsbeitrag
news:Pine.LNX.4.44.0407060654550.23516-100000@wobblini...
> Hi --
>
> On Tue, 6 Jul 2004, Robert Klemme wrote:
>
> > True.  The approach is betters suited to a method implementation:
> >
> > module Enumerable
> >   def index_2(obj=nil, &b)
> >     b = lambda {|x| obj == x} unless b
> >     inject(0) {|i,el| return i if b.call(el); i+1}
> >     nil
> >   end
> > end
>
> I agree.  My version, for what it's worth, was:
>
>   module Enumerable
>     def b_index
>       each_with_index {|e,i| return i if yield(e) }
>       nil
>     end
>   end
>
> I decided to make it orthogonal to #index, rather than a superset of
> it, on the theory that it would be good to avoid making it legal to
> give both an argument and a block.

Might be best to just enhance #index with the block variant.

>  I also like #each_with_index
> here, rather than #inject, only because it does more of the work and
> eliminates the need for manually incrementing an index.  I haven't
> benchmarked them though.

True.  I was blind for that because of my strong #inject affection... :-)

Regards

    robert