Hope you can help me, this thing is driving me crazy. I'm trying to validate user input, which is a list of comma separated numbers.Only the lists of values which contain at least one of the following single digits should pass: 1, 2, 3. For example, the following list of values are valid:
- 1,6,9,7
- 3
- 65,2
- 46,57,1,6
Whereas the following is not:
222,111,33
9,8,7
4,5,6
111
CodePudding user response：
/\b[123]\b/g a single class of 1, 2, or 3 surrounded by word boundaries. Word boundaries (\b) are matched by a word and then matched by a non-word:
\b⇩ ⇩\b
1,
CodePudding user response：
^(?:\d ,)*[123](?:,\d )*$
Basically how the above works are is it captures any valid sequence before and after a valid number and if there are no fails it is successful.
^ 'start
(?:\d ,)* 'match as many as we want before ie. 44,33,44,55,
[123] 'match our number
(?:,\d )* 'match as many as we want after ie ,0,2,5
$ 'should be the end of the string