Regex - Ignore if group has prefix

Question

I am trying to capture 8 digit phone numbers in free text. This should be ignored if a particular string appears before.

My regex:

(\b(\+?001|002)?[-]?\d{4}(-|\s)?\d{4}\b)

To Capture:

+001 12345678
12345678

Not Capture:

TTT-12345678-123
TTT-12345678

I am trying to use negative look behind as below example:

\w*(?<!foo)bar

But the above works only if the regex doesn't have subsequent groups.

This will capture the last 8 digits in a 10 digit number also. eg: >1234567896 — blackfury, Jul 01 '20 at 09:04
No, it won't, see [the regex demo](https://regex101.com/r/WyvDZY/2). — Wiktor Stribiżew, Jul 01 '20 at 09:09
-12345678-, <12345678> will not be captured. @WiktorStribiżew: Actually i dont want to capture 8 digit numbers only after this specific string "TTT". But no:12345678 should still be captured — blackfury, Jul 01 '20 at 09:14
Got it, try `(?<!TTT-)(?<!\w)(?:\+?001|002)?[-\s]?\d{4}[-\s]?\d{4}\b`, see [this regex demo](https://regex101.com/r/WyvDZY/3). — Wiktor Stribiżew, Jul 01 '20 at 09:16

score 1 · Accepted Answer · answered Jul 01 '20 at 09:31

You may use

(?<!TTT-)(?<!\w)(?:\+?001|002)?[-\s]?\d{4}[-\s]?\d{4}\b

Details

(?<!TTT-) - no TTT- allowed immediately on the left
(?<!\w) - no word char allowed immediately on the left
(?:\+?001|002)? - an optional non-capturing group matching 1 or 0 occurrences of +001, 001 or 002
[-\s]? - an optional - or whitespace
\d{4} - any four digits
[-\s]?\d{4} - - an optional - or whitespace and any four digits
\b - a word boundary.

If the number can be glued to a word char on the right, replace the \b word boundary with the right-hand digit boundary, (?!\d).

1 Answers1