Exclude a certain match in a capturing group in regex

Question

I have a regex capturing group and I want to exclude a number if it matches a certain pattern also.

This is my capturing group:

https://regex101.com/r/zL1tL8/1

if \n is followed by a number and character like "1st", "2nd", "4dffgsd", "3sf" then it should stop the match BEFORE the number.

0-9 is important in the capturing group.

So far I have this pattern [0-9][a-zA-Z]+ to match a number followed by characters. How do I apply this to the capturing group as a condition?

Update:

https://regex101.com/r/zL1tL8/4

Line 1 is wrong.

It should not match a number followed by characters

Solution

You'll want to use a negative lookahead to "stop" the match if something after matches your pattern. So, something like this might work:

(\\n(?![0-9][a-zA-Z]))

See it in use here: https://regex101.com/r/zL1tL8/2

Here's a page with some more info on lookahead and lookbehind: http://www.rexegg.com/regex-lookarounds.html

Comments

[Admin]

Can you post the text of the regex instead of a link to it.

[Admin]

It's unclear if \n is a newline (0x0a) or a literal \ plus n. It's also nclear what you are trying to match.

[oyan11]

Hi, i edited the sample regex already. what i really want is to un match if there's a number followed by characters \n1st should not match 1st. but it should match \n$300 or \n599

[Jake Bathman]

Did you look at my answer below? It should do what you're looking for.

[Jon]

It is assumed that the OP knows then how to then capture everything after "\n", but for completeness's sake, ^\\n(?![0-9][A-Z])(.+)$ contains a capturing group that captures everything after the "\n" (as "i" was used in linked example, I omitted the "a-z" from the character class). "^" and "$" anchors are necessary given "m" modifier.