Regex match entire words only

Question

I have a regex expression that I m using to find all the words in a given block of content  case insensitive  that are contained in a glossary stored in a database  Here s my pattern      word  i   The problem is  if I use   Foo  i then words like Food get matched   There needs to be whitespace or a word boundary on both sides of the word   How can I modify my expression to match only the word Foo when it is a word at the beginning  middle  or end of a sentence

User · Answer

use word boundaries  b   The following  using four escapes  works in my environment  Mac  safari Version 10 0 3  12602 4 8   var myReg   new RegExp        b     variable          b        g

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Using  b can yield surprising results  You would be better off figuring out what separates a word from its definition and incorporating that information into your pattern      usr bin perl  use strict  use warnings   use re  debug    my  str    S P E C T R E   Special Executive for Counter-intelligence  Terrorism  Revenge and Extortion  is a fictional global terrorist organisation    my  word    S P E C T R E     if    str      b  Q word E  b          print  1    n       Output    Compiling REx   b S  P  E  C  T  R  E    b  Final program     1  BOUND  2     2  OPEN1  4     4    EXACT   9     9  CLOSE1  11    11  BOUND  12    12  END  0  anchored  S P E C T R E   at 0  checking anchored  stclass BOUND minlen 14 Guessing start of match in sv for REx   b S  P  E  C  T  R  E    b  against  S P  E C T R E   Special Executive for Counter-intelligence      Found anchored substr  S P E C T R E   at offset 0    start shift  0 check at  0 s  0 endpos  1 Does not contradict STCLASS    Guessed  match at offset 0 Matching REx   b S  P  E  C  T  R  E    b  against  S P E C T R E   Special Exec utive for Counter-intelligence         0              1 BOUND 2     0              2 OPEN1 4     0              4 EXACT  9    14         9 CLOSE1 11    14        11 BOUND 12                                    failed    Match failed Freeing REx    b S  P  E  C  T  R  E    b

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Use word boundaries     b  word  b i   Or if you re searching for  S P E C T R E   like in Sinan   n  r s example        W     Q word E     W    i

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To match any whole word you would use the pattern   w    Assuming you are using PCRE or something similar     Above screenshot taken from this live example  http   regex101 com r cU5lC2  Matching any whole word on the commandline with   w    I ll be using the phpsh interactive shell on Ubuntu 12 10 to demonstrate the PCRE regex engine through the method known as preg match  Start phpsh  put some content into a variable  match on word   el apollo   foo  phpsh  php gt   content1    badger  php gt   content2    1234  php gt   content3        amp    php gt  echo preg match    w      content1   1  php gt  echo preg match    w      content2   1  php gt  echo preg match    w      content3   0   The preg match method used the PCRE engine within the PHP language to analyze variables   content1   content2 and  content3 with the   w   pattern      content1 and  content2 contain at least one word   content3 does not   Match a number of literal words on the commandline with  dart fart   el apollo   foo  phpsh  php gt   gun1    dart gun   php gt   gun2    fart gun   php gt   gun3    farty gun   php gt   gun4    unicorn gun    php gt  echo preg match   dart fart     gun1   1  php gt  echo preg match   dart fart     gun2   1  php gt  echo preg match   dart fart     gun3   1  php gt  echo preg match   dart fart     gun4   0   variables gun1 and gun2 contain the string dart or fart   gun4 does not   However it may be a problem that looking for word fart matches farty   To fix this  enforce word boundaries in regex   Match literal words on the commandline with word boundaries   el apollo   foo  phpsh  php gt   gun1    dart gun   php gt   gun2    fart gun   php gt   gun3    farty gun   php gt   gun4    unicorn gun    php gt  echo preg match    bdart b  bfart b     gun1   1  php gt  echo preg match    bdart b  bfart b     gun2   1  php gt  echo preg match    bdart b  bfart b     gun3   0  php gt  echo preg match    bdart b  bfart b     gun4   0   So it s the same as the previous example except that the word fart with a  b word boundary does not exist in the content  farty

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If you are doing it in Notepad      w      Would give you the entire word  and you can add parenthesis to get it as a group  Example  conv1   Conv2D 64   3  3   activation LeakyReLU alpha a   padding  valid   kernel initializer  he normal   inputs   I would like to move LeakyReLU into its own line as a comment  and replace the current activation  In notepad   this can be done using the follow find command      w           LeakyReLU alpha a         and  the replace command becomes    1 2 relu  4  n       1   LeakyReLU  alpha a     1     The spaces is to keep the right formatting in my code

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For Those who want to validate an Enum in their code you can following the guide In Regex World you can use   for starting a string and   to end it  Using them in combination with   could be what you want     Male     Female   It will return true only for Male or Female case

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Get all  words  in a string       s    g     Basically   s means break on spaces  or match groups of non-spaces    Don t forget the g for Greedy

[regex] Regex match entire words only

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