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?
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