Capture repeated letters in regex apart from the first letter matched

Question

I'm trying to get a regex that captures repeated letters except for the first letter that is matched.

I have a regex that gets the repeated letters: ([a-z])\1{2,}

However this would capture "ooo" in sooo. But i would only want to capture "oo"

(using this for the find and replace function in google sheets)

`([a-z])(\1+)` is this what you want? (just throw away the first capture) — mukunda, May 18 '20 at 02:03

ICloneable · Accepted Answer · 2020-05-18T02:13:08.930

Since you didn't mention what programming language or regex flavor you're using, I will provide multiple options:

Use a capturing group:
```
([a-z])(\1{2,})
```
Demo.

This will work with every regex flavor but your expected match would be in the second capturing group.
If your regex flavor supports Lookarounds, use a positive Lookbehind:
```
(?<=([a-z]))\1{2,}
```
Demo.
If your regex flavor supports \K, you can use the following:
```
([a-z])\K\1{2,}
```
Demo.

Note that \1{2,} means that you'll have a match only if the letter is repeated at least 3 times (e.g., aaa). If that's not what you intended and you want to have a match when the letter is repeated twice, you should use \1+ instead.

Capture repeated letters in regex apart from the first letter matched

1 Answers1