Regular expression to extract text between square

Question

Simple regex question. I have a string on the following format:

this is a [sample] string with [some] special words. [another one]

What is the regular expression to extract the words within the square brackets, ie.

sample
some
another one

Note: In my use case, brackets cannot be nested.

Answer 1

This should work out ok:

\[([^]]+)\]

Answer 2

(?<=\[).+?(?=\])

Will capture content without brackets

• (?<=\[) - positive lookbehind for [

• .*? - non greedy match for the content

• (?=\]) - positive lookahead for ]

EDIT: for nested brackets the below regex should work:

(\[(?:\[??[^\[]*?\]))

Answer 3

Can brackets be nested?

If not: \[([^]]+)\] matches one item, including square brackets. Backreference \1 will contain the item to be match. If your regex flavor supports lookaround, use

(?<=\[)[^]]+(?=\])

This will only match the item inside brackets.

Answer 4

(?<=\().*?(?=\)) works good as per explanation given above. Here's a Python example:

import re 
str =    "Pagination.go('formPagination_bottom',2,'Page',true,'1',null,'2013')"
re.search('(?<=\().*?(?=\))', str).group()
"'formPagination_bottom',2,'Page',true,'1',null,'2013'"

Answer 5

This code will extract the content between square brackets and parentheses

(?:(?<=\().+?(?=\))|(?<=\[).+?(?=\]))

(?: non capturing group
(?<=\().+?(?=\)) positive lookbehind and lookahead to extract the text between parentheses
| or
(?<=\[).+?(?=\]) positive lookbehind and lookahead to extract the text between square brackets

Answer 6

([[][a-z \s]+[]])

Above should work given the following explaination

• characters within square brackets[] defines characte class which means pattern should match atleast one charcater mentioned within square brackets

• \s specifies a space

•  + means atleast one of the character mentioned previously to +.