RegEx for matching all chars except for comma separated digits

Question

I have an input that I want to apply validation to. User can type any integer (positive or negative) numbers separated with a comma. I want to

Some examples of allowed inputs:

1,2,3
-1,2,-3
3
4
22,-33

Some examples of forbidden inputs:

1,,2
--1,2,3
-1,2,--3
asdas
[]\%$1

I know a little about regex, I tried lots of ways, they're not working very well see this inline regex checker:

^[-|\d][\d,][\d]

Maybe `(?:\W|^)(-?\d+(?:,-?\d+)*)\b` will work for you, or `-?\b\d+(?:,-?\d+)*\b` — Wiktor Stribiżew, May 24 '19 at 10:47

CertainPerformance · Accepted Answer · 2019-05-24T10:58:35.923

4

You can use

^(?:-?[0-9]+(?:,(?!$)|$))+$

-? - Lead with optional -
[0-9]+ - Repeat digits
(?:,(?!$)|$)) - After the digits, match either a comma, or the end of the string. When matching a comma, make sure you're not at the end of the string with (?!$)

edited May 24 '19 at 10:58

answered May 24 '19 at 10:46

Oh, good point - just negative lookahead for `$` after matching a comma – CertainPerformance May 24 '19 at 10:58
Hi! thanks for the great answer. how can I change this regex to allow spaces between two numbers, something like this: `1,2, 3, -4, 5,6,7` – Ahmad Mobaraki Jun 08 '19 at 20:51
Repeat 0 or more spaces after matching the comma: https://regex101.com/r/PAyar7/3 – CertainPerformance Jun 08 '19 at 21:24
Thanks a ton! I really appreciate your help – Ahmad Mobaraki Jun 09 '19 at 04:31

bobble bubble · Answer 2 · 2019-05-24T15:59:22.250

As per your requirements I'd use something simple like

^-?\d+(?:,-?\d+)*$

at start ^ an optional minus -? followed by \d+ one or more digits.
followed by (?:,-?\d+)* a quantified non capturing group containing a comma, followed by an optional hyphen, followed by one or more digits until $ end.

Another perhaps harder to understand one which might be a bit less efficient:

^(?:(?:\B-)?\d+,?)+\b$

The quantified non capturing group contains another optional non capturing group with a hyphen preceded by a non word boundary, followed by 1 or more digits, followed by optional comma.
\b the word boundary at the $ end ensures, that the string must end with a word character (which can only be a digit here).

You can test this one here at regex101

2 Answers2