Regex excluding square brackets

Question

I am new to regex. I have this regex:

\[(.*[^(\]|\[)].*)\]

Basically it should take this:

[[a][b][[c]]]

And be able to replace with:

[dd[d]]

abc, d are unrelated. Needless to say the regex bit isn't working. it replaces the entire string with "d" in this case.

Any explanation or aid would be great!

EDIT:

I tried another regex,

\[([^\]]{0})\]

This one worked for the case where brackets contain no inner brackets and nothing else inside. But it doesn't work for the described case.

Answer 1

You need to know that . dot is special character which represents "any character beside new line mark" and * is greedy so it will try to find maximal match.

In your regex \[(.*[^(\]|\[)].*)\] first .* will represent maximal set of characters between [ and [^(\]|\[)].*)\]] and this part can be understood as non [ or ] character, optional other characters .* and finally ]. So this regex will match your entire input.

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To get rid of that problem remove both .* from your regex. Also you don't need to use | or ( ) inside [^...].

System.out.println("[[a][b][[c]]]".replaceAll("\\[[^\\]\\[]\\]", "d"));

Output: [dd[d]]