Regex expression to invalidate numbers separated by comma-CodePudding

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]*[^,]

CodePudding user response：

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.