From: botp <botpena@...>
Date: 2011-01-11T11:48:14+09:00
Subject: Re: Best way for Array#find+transform ?

On Mon, Jan 10, 2011 at 11:14 PM, Jonas Pfenniger (zimbatm)
<jonas@pfenniger.name> wrote:
> 2011/1/10 David J. Hamilton <groups@hjdivad.com>:
>> My version is slightly verbose.  As w_a_x_man@yahoo.com implicitly pointed out
>> in their version, the false in the block is actually unnecessary, since the
>> conditional will evaluate to nil, thus allowing the iteration to continue.
>
> Right, now we have the perfect version :)
>
>> Break is indeed nice.  And of course you can sometimes do the same thing with
>> return, although I think it's usually much cleaner to break out of blocks rather
>> than returning out of them (and the method in which they're evaluated).
>
> Yeah I agree, return is less clean because it doesn't express the
> intent of exiting that particular algorithm.

no on all.  on your case, one does not need break nor return. #find
will shortcircuit and returns the first find, or nil otherwise. iow,
the ff should do,

   paths.find{|path| File.exists?(File.join(path,filename))}


in fact, find is quite flexible, it allows you to exec/return
something (override) the returned nil by passing a lambda/proc. eg,

   nothing= ->{puts "nothing here, passing a null string instead"; ""}
   #=> #<Proc:0x8cb327c@(irb#1):90 (lambda)>

   paths.find(nothing){|path| File.exists?(File.join(path,filename))}
   nothing here, passing a null string instead
   #=> ""

best regards -botp