From: mental@...
Date: 2005-12-08T08:08:23+09:00
Subject: Re: increasing counter whithin loop?

Quoting Patrick Gundlach <clr9.10.randomuser@spamgourmet.com>:

> sequence.each do |element|
>  ....
> end
>
> would be nice, but I understand that there is no
> 'skip_the_next_element'-method. So the next nicer attempt would
> be
>
> for counter in 0...element.size
>   # ...
>   increase_counter_by_one_to_skip_one_interation
> end
>
> But - contradicting my intuition - doesn't seem to work/exist. So
> I have to stick to an ugly while loop.... ;-) So my question is:
> did I miss something?

There's really no difference between:

 for counter in 0...element_size
   ...
 end

and

 (0...element_size).each do |counter|
   ...
 end

Both call Range#each with the given block.

> Is there any reason why we can't manipulate the counter within
> the loop?

'counter' isn't actually a counter.  It's just a parameter of the
block given to Range#each.  While there's probably a real counter
behind the scenes somewhere, it's not exposed to you.

90% of the time you don't need counters or while loops, though. 
Even here, there's nothing preventing you from doing e.g.:

 skip = false
 sequence.each do |element|
   if skip
     skip = false
     next
   end
   ...
   # set skip to true to skip the next iteration
   ...
 end

or alternately:

 skip = false
 sequence.each do |element|
   unless skip
     ...
     # set skip to true to skip the next iteration
     ...
   end
   skip = false
 end

-mental