Regex for everything but a specific character not preceded by a string

Question

I am out of luck getting a regex build together which machtes everything but a specific character not preceded by a specific string.

For example this String:

Mr. Jones likes fish.

Should match like this:

Mr. Jones likes fish

And not for example:

Mr

I think this should be really easy but it just won't work. I already have it working for getting a correct match on the dot:

(?<!Mr)\.

The complementary match won't work though. I tried this:

(?<!Mr)[^.]*

Because i thought the cursor would be on the dot at that point and see that it was proceded by the "Mr" and it won't match. But it does.

And something like this:

(^((?<!Mr).))*

But the lookbehind in that regex is not recognized as one anymore and it just tries to match each character.

I already saw this answer but i couldn't find anythin helping me there.

Your question is good apart from the last paragraph (*im struggling*, *help me fast* etc). — achAmháin, Jun 10 '18 at 18:13
So you want a regexp to match anything except strings that has a `\.` after `Mr` somewhere? Is`Mr` always in the string only once? — Sylwester, Jun 10 '18 at 18:16
Sounds to me like you want to match any character besides the period with the exception it is preceded by `Mr` so the regex could be [`"(?:[^.]+|(?<=Mr)\\.)+"`](https://regex101.com/r/N42EHf/1) — bobble bubble, Jun 10 '18 at 18:22
@Sylwester I want a regexp that matches everything but `\.` not preceded by a `Mr`. `Mr` can also be more often in the string. — systderr, Jun 10 '18 at 18:29
@bobblebubble Yes! Thank you. That works perfectly. The `or` does the trick. — systderr, Jun 10 '18 at 18:34
@bobblebubble If you post you comment as an answer, I can accept it. — systderr, Jun 10 '18 at 18:37

score 3 · Accepted Answer · answered Jun 10 '18 at 18:52

As it looked to me, you want to match any character besides . with the exception that the period is preceded by Mr so you could use an alternation (or an optional group) and a lookbehind.

(?:[^.]+|(?<=Mr)\.)+

As a Java String: "(?:[^.]+|(?<=Mr)\\.)+"

Here is a demo at regex101 (non Java)

(?: opens a non capturing group
[^.]+ matches one or more characters that are not .
(?<=Mr)\. matches the period only if preceded by Mr

Regex for everything but a specific character not preceded by a string

1 Answers1