Search and replace in Visual Studio

Question

In Visual Studio, when I search within a selection, I want to replace the first instance (or second, third, etc.) of a match per line using regular expressions. How would I

Answer 1

If you would be more variable:

Regex.Replace(input, @"(?<=\= )[^;0-9]*(?=[0-9]*;)", replacewith);

This search for = and (anynumber); and replace that between.

Edit: The number is optional.