Home Java How would you create a regex that only allows numbers 3,4,6 or 9 and in the regex a sequence of numbers consisting of 3 numbers must repeat?

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Java How would you create a regex that only allows numbers 3,4,6 or 9 and in the regex a sequence of numbers consisting of 3 numbers must repeat?

byMR

January 7, 2022

I need a regex that only allows these numbers and checks if a tripple occurs, how would I do that? (For Java)

>Solution :

I’d use the following pattern which you can try out here.

^[3469]*(333|444|666|999)[3469]*$

Token	Explanation
`^`	Start at the beginning of the line
`[3469]*`	Match `3`, `4`, `6`, or `9` zero or more times
`(333\|444\|666\|999)`	Match a triple
`[3469]*`	Match `3`, `4`, `6`, or `9` zero or more times
`$`	Stop at the end of the line