From: Lloyd Linklater <lloyd@2live4.com>
Date: 2007-11-21T14:49:40+09:00
Subject: Re: for loop

Martin Durai wrote:
> Consider the following for loop in 'C' or 'c++' or 'java'
> 
>           for (i=namespaceEnd - 1; i >= 0; i--)
> 
> Please help me with code to do the same functionality in ruby

ruby does not really have a for loop as such but there are various ways 
to get the job done.  You saw the upto approach.  Here is another:


namespaceEnd.times do
  # your code in here
end

now, this works for 0..namespace - 1 automatically.  If you need to run 
in reverse, can use the downto or a calculation.

namespaceEnd.times do |my_var|
  some_array[namespaceEnd - my_var] = some_val
end

but that is clunky.  If you are iterating through an array you can use 
the each loop:

my_arr = ["aaa", "bbb", "ccc", "ddd"]
my_arr.each_with_index {|str, idx| puts "#{idx}. #{str}"}

=>
0. aaa
1. bbb
2. ccc
3. ddd

If you want only the values, use my_arr.each
If you want only the index position, use my_arr.each_index

HTH
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