What does regex expression match pattern "\\[.*\\]" mean?

Question

I am new to regex. What does regex expression match pattern "\[.*\]" mean?

If I have a text like "Hello [Here]", then success is returned in the match. And match contain [Here].

I read that:

. indicates Any except \n (newline),
* indicates 0 or more times

I don't understand the "\". It believe it is just escape sequence for "\".

So, is the expression "\[.*\]" trying to match a pattern like \[Any text\]?

There is no `\.` in your pattern. It's `\[` to match `[` literal as `[` in regex is character class, it need to escaped to match opening square bracket. — Tushar, Dec 28 '16 at 06:48
_is the expression "\[.*\]" trying to match a pattern like [Any text] ?_ Yes. It'll match text wrapped inside square brackets. But fail when there is nested brackets. — Tushar, Dec 28 '16 at 06:49

score 0 · Accepted Answer · answered Dec 28 '16 at 06:50

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Yes, you are right. It will match any characters enclosed in []. The .* imply any or no characters enclosed in []. Also you should try this link which is a very helpful regex tool. You can input the regex pattern and check for matches easily.

answered Dec 28 '16 at 06:50

Hima Varsha

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Thanks! But what is the significance of backslash (\\) in the expression "\\[.*\\]"? – Veeru Dec 28 '16 at 06:59
Backslash forces a special regex character to be interpreted literally. – Veeru Dec 28 '16 at 09:17
Here's a good site for regex: http://misc.yarinareth.net/regex.html – Veeru Dec 28 '16 at 09:18

score 0 · Answer 2 · edited Dec 28 '16 at 09:03

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I have tried this on regexr, here is a screen shot:

edited Dec 28 '16 at 09:03

halfer

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answered Dec 28 '16 at 06:51

Lucifer

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What does regex expression match pattern "\\[.*\\]" mean?

2 Answers2