GREP regexr

I wanted a simple patch to add a certain number of zero's after the decimal point in a float when its value is zero (so the text layout doesn't jump when it starts to change).

While there are a few of ways that come to mind of doing this without grep I got started down that path, probably b/c I have a bad habit of making work for myself if it means learning another technique that's new to me.

If found a great online set of video tutes for GREP but after the first tute no clue as to how to accomplish this despite a few different angles of attack.

Tutes: http://blog.themeforest.net/screencasts/regular-expressions-for-dummies/ Testbed: http://gskinner.com/RegExr/

This is an academic kind of "how is this done exactly?" with GREP b/c I know it's powerful and I want to learn it one of these days.