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ViewsMatch a line with a [ character, but don't match if it has a ] character
I thought this regex would match lines with a [, but not if it has a ]:
^.*\[.*(?!\]).*$
Instead, it's matching every line with a [ (shown in bold):
This [should match]. This line should match
This line shouldn't match.
This line shouldn't match. This line [shouldn't match.
How to fix that regex so that it doesn't match lines that have a ]?
This [should match]. This line should match
This line shouldn't match.
This line shouldn't match. This line [shouldn't match.
Demo: https://regexr.com/67qk7
3 answers
Answer question0
This pattern ^.*\[.*(?!\]).*$ matches [ and the directly following .* will match the rest of the line.
Then at the end of the line it will assert not ] directly to the right, which is true because it already is at the end of the line. Then the .* is optional and it can assert the end of the string.
So it will match any whole line that has at least a single [
If you want to match pairs of opening till closing square brackets [...] and not allow any brackets inside it, or single brackets outside of it and matching at least a single pair, you can repeat 1 or more times matching pairs surrounded by optional chars other than square brackets.
^(?:[^\][\n]*\[[^\][\n]*\])+[^\][\n]*$
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An alternate solution which is not super efficient but is a bit shorter:
^(?!.*\[[^\]\n]*$)[^[\n]*\[.+$
Explanation:
(?!.*\[[^\]\n]*$)fails the match if we get a[without a closing]anywhere[^[\n]*\[matches first[in a line
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"This regex would match lines with a [" (one or more), "but not if it has a ]" (one or more):
^[^\][\n]*\[[^\]\n]*$
