Regular expression to extract text between square brackets

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

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If someone wants to match and select a string containing one or more dots inside square brackets like  quot  fu bar  quot  use the following     lt       w    w             Regex Tester

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You can use the following regex globally               Explanation           is a meta char and needs to be escaped if you want to match it literally          match everything in a non-greedy way and capture it         is a meta char and needs to be escaped if you want to match it literally

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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      lt                   This will only match the item inside brackets

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lt                 Will capture content without brackets      lt      - positive lookbehind for       - non greedy match for the content        - positive lookahead for     EDIT  for nested brackets the below regex should work

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This should work out ok

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Just in case  you might have had unbalanced brackets  you can likely design some expression with recursion similar to                   R         which of course  it would relate to the language or RegEx engine that you might be using    RegEx Demo 1    Other than that              r n        RegEx Demo 2  or       lt            r n           RegEx Demo 3  are good options to explore      If you wish to simplify modify explore the expression  it s been explained on the top right panel of regex101 com  If you d like  you can also watch in this link  how it would match against some sample inputs     RegEx Circuit  jex im visualizes regular expressions      Test   x000D   x000D  const regex              r n      gm  x000D  const str    This is a  sample  string with  some  special words   another one  x000D  This is a  sample string with  some special words   another one x000D  This is a  sample sample   string with   some  some   special words    another one     x000D  let m  x000D   x000D  while   m   regex exec str       null    x000D         This is necessary to avoid infinite loops with zero-width matches x000D      if  m index     regex lastIndex    x000D          regex lastIndex    x000D        x000D       x000D         The result can be accessed through the  m -variable  x000D      m forEach  match  groupIndex    gt    x000D          console log  Found match  group   groupIndex     match     x000D          x000D    x000D   x000D   x000D    Source  Regular expression to match balanced parentheses

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The  Tim Pietzcker s answer here     lt                   is almost the one I ve been looking for  But there is one issue that some legacy browsers can fail on positive lookbehind  So I had to made my day by myself     I manged to write this                g  Maybe it will help someone   x000D   x000D  console log  this is a  sample  string with  some  special words   another one   match               g    x000D   x000D   x000D

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This code will extract the content between square brackets and parentheses        lt                  lt                     non capturing group    lt               positive lookbehind and lookahead to extract the text between parentheses   or    lt               positive lookbehind and lookahead to extract the text between square brackets

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If you do not want to include the brackets in the match  here s the regex     lt                Let s break it down  The   matches any character except for line terminators  The    is a positive lookahead  A positive lookahead finds a string when a certain string comes after it  The   lt   is a positive lookbehind  A positive lookbehind finds a string when a certain string precedes it  To quote this       Look ahead positive           Find expression A where expression B follows       A   B       Look behind positive    lt         Find expression A where expression B   precedes           lt  B A   The Alternative  If your regex engine does not support lookaheads and lookbehinds  then you can use the regex           to capture the innards of the brackets in a group and then you can manipulate the group as necessary   How does this regex work   The parentheses capture the characters in a group  The     gets all of the characters between the brackets  except for line terminators  unless you have the s flag enabled  in a way that is not greedy

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if you want fillter only small alphabet letter between square bracket a-z      a-z        if you want small and caps letter a-zA-Z      a-zA-Z         if you want small  caps and  number letter a-zA-Z0-9      a-zA-Z0-9         if you want everything between square bracket  if you want text   number and symbols

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In R  try   x  lt -  foo bar baz  str replace x                         1    1   bar

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I needed including newlines and including the brackets      s S

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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

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To match a substring between the first   and last    you may use                      Including open close brackets                     Excluding open close brackets  using a capturing group     lt                  Excluding open close brackets  using lookarounds    See a regex demo and a regex demo  2   Use the following expressions to match strings between the closest square brackets    Including the brackets              - PCRE  Python re regex   NET  Golang  POSIX  grep  sed  bash             - ECMAScript  JavaScript  C   std  regex  VBA RegExp              - Java regex              - Onigmo  Ruby  requires escaping of brackets everywhere   Excluding the brackets       lt                 - PCRE  Python re regex   NET  C   etc    ICU  R stringr   JGSoft Software             - Bash  Golang - capture the contents between the square brackets with a pair of unescaped parentheses  also see below              - JavaScript  C   std  regex  VBA RegExp    lt                   - Java regex    lt                    - Onigmo  Ruby  requires escaping of brackets everywhere     NOTE    matches 0 or more characters  use   to match 1 or more to avoid empty string matches in the resulting list array   Whenever both lookaround support is available  the above solutions rely on them to exclude the leading trailing open close bracket  Otherwise  rely on capturing groups  links to most common solutions in some languages have been provided    If you need to match nested parentheses  you may see the solutions in the Regular expression to match balanced parentheses thread and replace the round brackets with the square ones to get the necessary functionality  You should use capturing groups to access the contents with open close bracket excluded                    R      - PHP PCRE       gt           lt o gt        lt -o gt        -  NET demo                  g lt 0 gt       - Onigmo  Ruby  demo

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lt               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     lt                 str  group     formPagination bottom  2  Page  true  1  null  2013

[regex] Regular expression to extract text between square brackets

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