I've been trying to use RegExp in JS to test a string for a certain count of a substrings. I would like a purely RegExp approach so I can combine it with my other search criteria, but have not had any luck.
As a simple example I would like to test a word if it has exactly 2-3 as.
| case | test string | expected result |
|---|---|---|
| 1 | cat |
false |
| 2 | shazam |
true |
| 3 | abracadabra |
false |
Most of my guesses at regex fail case 3. Example: ^(?<!.*a.*)((.*a.*){2,3})(?!.*a.*)$
CodePudding user response：
Could use this regex.
With any other character, including whitespace.
^[^a]*(?:a[^a]*){2,3}$
or if using multi-lines and don't want to span.
^[^a\r\n]*(?:a[^a\r\n]*){2,3}$
^ # Begin
[^a]* # optional not-a
(?: # Grp
a # single a
[^a]* # optional not-a
){2,3} # Get 2 or 3 a only
$ # End