From: Robert Klemme <shortcutter@...>
Date: 2007-05-10T21:50:06+09:00
Subject: Re: loop questions

On 10.05.2007 14:33, Lloyd Linklater wrote:
> I am new to ruby and loving it so far and have beginner's questions
> about loops.
> 
> I wanted something like this:
> 
> for (int i = 1; i <= 5; i++)
>   printf("%d\n", [i]);
> 
> expecting:
> 
> 1
> 2
> 3
> 4
> 5
> 
> 
> I wrote this:
> 
> i = 5
> 
> i.times do
>   puts i.to_s
> end
> 
> And got:
> 
> 5
> 5
> 5
> 5
> 5
> 
> I am guessing that there is an internal variable that is incremented.
> doh!  Is there a way to get the changing variable in there without
> having a separate variable in there?

The current value us passed to the block.  So rather do

5.times do |i|
   puts i
end

> Anyway, I then tried this:
> 
> for i in 1..5
>   puts i.to_s
> end

You don't need the to_s here as puts will do that automatically.

> 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?

5.downto 1 do |i|
   puts i
end

or

5.step 1, -1 do |i|
   puts i
end

If you think you need a /for/ loop:

for i in (1..5).to_a.reverse
   puts i
end

But I'd rather not do this.

Kind regards

	robert