From: Robert Klemme <shortcutter@...>
Date: 2007-04-07T16:00:04+09:00
Subject: Re: Newbie question - ruby equivalence of for loop?

On 07.04.2007 00:21, dwyer@o2.ie wrote:
> is there an equivalence in Ruby for the nested "for loop" in java.
> i want to complete the following:
> 		i is 0
> 				j is 2
> 				j is 4
> 				j is 6
> 				j is 8
> 		i is 1
> 				j is 2
> 				j is 4
> 				j is 6
> 				j is 8
> 		i is 2
> 				j is 2
> 				j is 4
> 				j is 6
> 				j is 8
> but want to use Ruby,(i think Rails has a foreach loop).I can do the above in Java 
> but Ruby is still foreign to me.Whats the best method to implement the above?

irb(main):005:0> 0.upto 2 do |i|
irb(main):006:1* 2.step 8, 2 do |j|
irb(main):007:2* print i, " ", j, "\n"
irb(main):008:2> end
irb(main):009:1> end
0 2
0 4
0 6
0 8
1 2
1 4
1 6
1 8
2 2
2 4
2 6
2 8
=> 0

You can also use a for loop for the outer loop:

irb(main):010:0> for i in 0..2 do
irb(main):011:1* puts i
irb(main):012:1> end
0
1
2
=> 0..2

The scoping is a bit different, i.e. i is known after the loop.

Kind regards

	robert