Take below strings for example
abc12, abc13, abc23, abc288, abd12
What regular string should be used if I only want to match abc12 and abc13.
I thought it should be abc[(12)|(13)], so 12 and 13 will be grouped together and match either of them, but it turns out, this string will match all strings above.
Your current regex is not doing what you think it is:
abc[(12)|(13)]
This says to match abc followed by any one of the following characters:
1, 2, 3, (, ), or |
The characters inside the bracket are part of a character class, or group of characters which can be matched. For your use case, you probably want something like this:
abc1[23]
This matches abc1 followed by only a 2 or a 3.
If you wanted to match abc12 or abc23 you could use this:
abc(?:12|23)
Here we can't really use a character class, but we can use an alternation instead. The quantity in parentheses will match either 12 or 23. If you are wondering what ?: does, it simply tells the Perl regex engine not to capture what is inside parentheses, which is what it would be doing by default.
$str =~ /^abc1(?:2|3)$/will match onlyabc12andabc13