From: Yukihiro Matsumoto <matz@...>
Date: 2006-04-20T08:00:24+09:00
Subject: Re: Array#each Looping Gotcha

Hi,

In message "Re: Array#each Looping Gotcha"
    on Thu, 20 Apr 2006 07:43:46 +0900, Nathan Olberding <nathan.olberding@gmail.com> writes:

|items.each do |x|
|	if x == ""
|		items.delete(x)
|	end
|end
|
|
|If items.each referred to items[] by reference, this would make sense. 
|But since it references by value, you're literally changing the array 
|live, as you're iterating through it. This means that, if you delete an 
|item in mid-iteration, you change the index of items[]. Since you 
|deleted something, you skip the next item.
|
|1) Do I have this right?

I'm not sure what you mean by the word "right" here.  It's ok for you
to write that kind of program, but I don't (can't) guarantee you will
get what you expect, although I try my best.  It might cost you much
to guarantee loop safety.  It shouldn't crash in any case though.

|2) Am I right in assuming that it's possible to create an infinite loop 
|this way by continually push()ing things on to items[]?

Yes, Ruby obeys you if you command it to loop infinitely.

							matz.