From: Brian Candler <b.candler@...>
Date: 2009-08-10T18:11:19+09:00
Subject: Re: loops vs blocks

Mathew Cucuzella wrote:
> The only situation where a 'for' loop seems more natural is when
> searching through an array, and you want to 'break' out when you find
> the element.  Breaking out of a block doesn't seem right, if it even
> works.

Breaking out of a block *is* the right thing to do. You can either use 
'break' just to break out of the block; 'return' to return from the 
enclosing method; or for more complex requirements there are catch and 
throw, although in practice those are almost never needed.

There are also predefined methods in Enumerable for searching through 
any enumerable object (such as an Array), e.g.

  arr = [["eggs",4], ["beans",15], ["cheese",12]]
  p arr.find { |x,y| y > 10 }

while or for loops are useful for iteration of indeterminite size, e.g.

  while line = STDIN.gets
    ... do stuff
  end

is probably clearer than

  loop do
    break unless line = STDIN.gets
    ... do stuff
  end

although in this particular case there is a natural iterator on STDIN 
anyway:

  STDIN.each_line do |line|
    ... do stuff
  end
-- 
Posted via http://www.ruby-forum.com/.