Trying to understand regular expression from legacy project

Question

In one codebase (PHP) I'm working on currently there is this regular expression:

!([a-z0-9]*)\.([a-zA-Z0-9]{3,4})

Which supposedly should match something like this:

a1213asddaa13124312ada.12ws

And yet it does not happen. Matching occurs only with this expression:

([a-z0-9]*)\.([a-zA-Z0-9]{3,4})

Can anybody clarify?

As far as I know "!" should not be a meta-character in PHP regex, so it was probably trying to match the "!" character exactly. You can see [this](https://regex101.com) website to test your regex in different language flavors. — Nicola Pellicanò, Sep 14 '17 at 15:08

score 1 · Accepted Answer · answered Sep 14 '17 at 15:09

1

! has no special meaning. It'll match a literal exclamation mark. a1213asddaa13124312ada.12ws does not start with one.

answered Sep 14 '17 at 15:09

John Kugelman

1 Answers1