I need to parse a regex with regex. I have a regex string:
[a-z]{1}[-][0-9]{4}[-][ab]
The actual regex for parsing the string above that I came up with and which almost works is:
/(?|\[(.*?)\]\{(.*?)\}|\[(.*?)\](.*?))/g
What does it do can be seen in this regex101 example and the error here is in the Match 2 and its Group 1 (-][0-9, which should be just -).
The goal is to match everything inside of square brackets [] followed by a number inside curly brackets {}. If curly brackets {} after square brackets [] are missing it should fill it with null and this is what alternative group is doing with branch reset group. Also if just square brackets followed by a square brackets, then it's expected to act as later as well (match what's on the inside of square brackets [] and fill Group 2 with null).
The problem that my regex doesn't stop on third [-] and matches it upto -][0-9 instead of matching just - and then starting with parsing [0-9]{4}.
The expected match should be:
[a-z]{1}
a-z
1
[-]
-
null
[0-9]{4}
0-9
4
[-]
-
null
[ab]
ab
null
The current match is incorrect and is as follows:
[a-z]{1}
a-z
1
[-][0-9]{4}
-][0-9
4
[-]
-
null
[ab]
ab
null
What am I missing?
CodePudding user response：
This regex should work:
\[([^]]*)](\{\d \}|)
Explanation:
\[- matches[([^]]*)- matches 0 occurrences of any character that is not a]and captures this submatch in group 1]- matches](\{\d \}|)- either matches nothing OR a{followed by 1 digits followed by}. Whatever is matched is stored in Group 2
CodePudding user response：
If you write these in JS, you should delete the first item in regex ( /(\[(.*?)\]\{(.*?)\}|\[(.*?)\](.*?))/g )
And if you want to check the difference between JS and PHP ( Php is the default in regex101) this link can be helpful.