Using regex to add leading zeroes

Question

I would like to add a certain number of leading zeroes (say up to 3) to all numbers of a string. For example:

Input: /2009/5/song 01 of 12

Outpu

Answer 1

Using c#:

string result = Regex.Replace(input, @"\d+", me =>
{
    return int.Parse(me.Value).ToString("0000");
});