Regular expression which does not match a string

Question

I am trying to find a regular expression which does not match the below string:

xxx_yyyyyy_zzz_aaaaa
xxx_yyyyyy_zzz_aaaaa_cat
xxx_yyyyyy_zzz_aaaaa_uom

My regular expression should get me only xxx_yyyyyy_zzz_aaaaa and not the ones which contain _cat and/or _uom. Basically I am trying to filter out rows with _cat and _uom from my rows using regex.

You need [`line anchors`](https://www.regular-expressions.info/anchors.html), i.e. `^xxx_yyyyyy_zzz_aaaaa$` — Code Maniac, Oct 07 '19 at 15:18
It could be anything xxx_yyyyyy_zzz_aaaaa is just a sample. it could also have yy_ff_ss_kk with yy_ff_ss_kk_cat and yy_ff_ss_kk_uom. I need to get only the yy_ff_ss_kk — vignesh asokan, Oct 07 '19 at 15:20
No. Only xyz_cat can match. but xyz_cat can match. Basically anything with _cat or _uom at the end should be filtered out by the regex — vignesh asokan, Oct 07 '19 at 15:26

Matt.G · Accepted Answer · 2019-10-07T15:47:59.750

1

Try Regex: (?:[a-z]+(?:_[a-z]+)*)(?<!_cat|_uom)\b

Demo

edited Oct 07 '19 at 15:47

answered Oct 07 '19 at 15:23

Matt.G

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Hi Matt. The regex should filter out any row with the values _cat and _uom at the end. It doesnt matter how many string groups are present in the front. – vignesh asokan Oct 07 '19 at 15:30
@vigneshasokan, I've updated the answer based on the new requirement – Matt.G Oct 07 '19 at 15:48
It is removing everything – vignesh asokan Oct 07 '19 at 15:49
what do you mean by "everything"? – Matt.G Oct 07 '19 at 15:53
It removed all 3 combinations instead of removing just the ones with _cat and _uom – vignesh asokan Oct 08 '19 at 12:51
see the Demo link in the answer, it only matches the ones without _cat or _uom at the end. – Matt.G Oct 08 '19 at 14:04

Regular expression which does not match a string

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