How to ignore a match based on a word if it appears before the match

Question

I have something like below

Payment Instrument modified. payment no: 5000000000000000, method: C for transponder: 5000000000000000 transponder type: A

In the above my regex need to match only 5000000000000000 which appeared after payment no:

Pattern: ([payment no: ][0-9]{4}[0-9]{0,16})([0-9]{4})

Answer 1

You can use the RegEx (?<=payment no: )\d+

• (?<=payment no: ) makes sure there is payment no: before your match

• \d+ matches any digit 1 or more times.

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A version without the lookbehind would be payment no: (\d+)

Demo.