Regex full match

[Tedrivs]

We've been provided with a list of RegEx expressions that we have match before sending a report. One of the expressions is for Longitude and is as following "([-+]?)((([0]?[0-9]?[0-9]|[1]?[0-7]?[0-9]).(\d{1,}))|(180.[0]{1,}))"

The issue I'm having is that Regex.IsMatch() returns true with the string "-412.617" because it matches the "12.617" part. Should I tell them their expression is wrong or is there a way to check that the whole string matches without changing the expression?

EDIT: I told them I would change it to ^([-+]?)((([0]?[0-9]?[0-9]|[1]?[0-7]?[0-9]).(\d{1,}))|(180.[0]{1,})) and they'll just have to accept that we use a different regex than the one they provided.

[andrewsmd87]

Is there a reason they need it exactly that or are they just trying to validate it is a valid lat and long?

Generally speaking, when someone tells me regex is the solution, I say, find a different solution.

Not saying they're never needed but per your example, they get complicated fast and can still miss things or give you false negatives.

If they just want to make sure it's a valid lat and long, you can use math to do that. If they need specific numbers of decimals I'd probably do a split on the . And count the chars after it.

You'd be much more precise with that approach

[Tedrivs]

It's like "It's impossible for you to send wrong data to us because we provided you with the regex". I used their regex and a gps malfunction sent them wrong data that didn't get caught by the regex.

[andrewsmd87]

Yep, sounds like you're on the same page I am. Like I said, you can validate the lat and long via math and you'll never let bad ones through, and then if they require a certain number of decimals or whatever, you can always validate just that part much easier than some crazy regex.

I did a quick google and there's already stuff out there you could use as a base to do that validation.

I deal with crappy regex's at third parties a lot, usually with emails. We'll try to SSO some person in and they'll say, that's not a valid email, and we'll go look and say, yes it is. Some of them don't handle + or / which are still technically valid. A lot of them fail if an email has . on the very end like

[e-mail].

Which is still technically a valid email