I have to make a regex expression to invalidate numbers which are separated by comma.
1_2_3 - valid
1_2_3,1_3 - invalid
What I have so far: ([1-9+_]*[1-9]*[^,]
I have to make a regex expression to invalidate numbers which are separated by comma.
1_2_3 - valid
1_2_3,1_3 - invalid
What I have so far: ([1-9+_]*[1-9]*[^,]
You can use
^\d+(?:_\d+)*$
See the regex demo. Details:
^ - start of string\d+ - one or more digits(?: - start of a non-capturing group:
_ - an underscore\d+)* - zero or more occurrences of the pattern sequences in the group$ - end of string.Note: in case the flavor is JavaScript, it is fine to use \d to match any ASCII digit and it is equal to [0-9]. If you need to match any number without leading zeros still accepting a 0, you may replace each \d with (?:0|[1-9]\d*) construct that matches a 0 or a digit other than 0 followed with any zero or more digits.