From: Martin DeMello <martindemello@...>
Date: 2003-06-09T18:19:09+09:00
Subject: Re: [RCR] join block

Simon Strandgaard <0bz63fz3m1qt3001@sneakemail.com> wrote:
> 
> So far I cannot think of any cases where I need to "join-pairs into a
> string". Can you show some more examples in order to convince me, that this
> actualy is usable ?     :-)

"{" << [1,2,3,"a","b",5,"c"].join {|x,y| 
   (x.type == y.type) ? "," : "} {" << "}"

#=> {1,2,3} {a,b} {5} {c}

words.join {|x,y| (x[-1] == ?.) ? "\n" : " "}

Even more useful, once we toss in the idea of a block, might be a
join_with_index:

[1,2,3,4,5,6,7,8,9].join_with_index {|x,y,i|
  (i % 3 == 2) ? "\n" : " "}

1 2 3
4 5 6
7 8 9

Though it'd be slightly confusing as to whether i referred to the index
of x or of y.

As for the block working on individual elements, that's map's job.

martin