Regex issue - asterisk after \d

Question

I'm using http://gskinner.com/RegExr/ to test my regex: [+-]?\d+\.?\d*(e[+-]?\d+)?. It's supposed to match floating point numbers. Currently it doesn't match .x, but I want to make it do that.

I tried changing it to [+-]?\d*\.?\d*(e[+-]?\d+)? (changed + to *) but that's an error. What's going wrong here?

Update: is it because everything is optional?

Answer 1

Change the \.? to \. and it will work:

[+-]?\d*\.\d*(e[+-]?\d+)?

I suppose that the point is not optional.

But if you want to make it so, then describe it better with [.]+.

As @h2ooooooo mentioned it seems to be a bug in the as3 implementation of regex.

\d+\.?\d+ // works
\d*\.?\d+ // works
\d*\.?\d* // does not work
\d?\.?\d? // does not work