From: "Mauricio Fernández" <batsman.geo@...>
Date: 2002-11-29T02:14:59+09:00
Subject: Re: Array#and? and Array#or? methods

On Thu, Nov 28, 2002 at 01:40:46PM +0900, Jeff de Vries wrote:
> 
> Thanks for pointing out Enumerable#detect.  I just started looking at 
> Ruby this week, and didn't think to look at methods other than in Array!
> 
> detect seems to work easily for the "or?" case:
> 
>  def even?(n)
>    (n&1) == 0
>  end
> 
>  [1,2,3].detect {|x| even? x}  ==> 2
> 
> (except that it returns the element found, rather than true or false, 
> which causes a problem if the found element is nil!)

I didn't know detect until I read about it in the reply to your first
message. It was quite a surprise (the magic word to trigger attention in
ruby-talk ;-) to find that it was an alias to Enumerable#find (or rather
the opposite), as I would have expected it to return 'true' or
'false'.
 
> For the "and?" case it is a bit awkward, though, because you have to "de 
> Morgan" the result and your test by negating them:
> 
>  ! [2,4,6].detect {|x| ! even? x}  ==> true
> 
> It sounds like Ruby 1.7 has what I want (except named all? and any?, but 
> that is okay ;^)
> 
> Thanks for the comments!
> 
> [BTW, I had to send/edit this reply twice to get it past SpamAssassin, 
> who kept rejecting it as spam!]

Please tell Shugo Maeda <shugo@ruby-lang.org>!
I'm sure he'll be glad to be taught how to write SPAM-style :-)
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/54448


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