Question

I am trying to match the following strings:

9
9.
9.5
.5

This is what I’ve produced so far to accomplish this:

(?<acreage>(?(\d+)((\.\d*)?)|(\.\d+)))

When I pass in 9.5, it returns NULL and .5 for acreage. I need it to pass back 9.5. What am I doing wrong?

Answer 1

So you have four situations:

1. Match something like x
2. Match something like x.y
3. Match something like x.
4. Match something like .y

So here you go:

\d+\.\d+|\d+\.?|\.d+

You can get rid of either of the last two possibilities by making digits in the first group optional, but not both. For instance:

\d*\.\d+|\d+\.?

Or, with a match group:

(?<acreage>\d*\.\d+|\d+\.?)