From: Brian Candler <B.Candler@...>
Date: 2007-05-10T22:00:58+09:00
Subject: Re: loop questions

On Thu, May 10, 2007 at 09:33:08PM +0900, Lloyd Linklater wrote:
> Which worked as expected.  But I had better use for a descending loop.
> In pascal it would be
> 
> for i := 5 downto 1 do
>   writeln('%d', [i]);
> 
> but I could not figure out how to do that in a for loop.  I looked
> through several books and could not find the answer.  Any tips?

http://www.rubycentral.com/book/tut_stdtypes.html

"Integers also support several useful iterators. We've seen one
already---7.times in the code example on page 47. Others include upto and
downto, for iterating up and down between two integers, and step, which is
more like a traditional for loop.

3.times        { print "X " }
1.upto(5)      { |i| print i, " " }
99.downto(95)  { |i| print i, " " }
50.step(80, 5) { |i| print i, " " }

produces:

X X X 1 2 3 4 5 99 98 97 96 95 50 55 60 65 70 75 80"

(Or better, buy the second edition in paper or PDF form)

Regards,

Brian.