Escaping a forward slash in a regular expression

Question

My question is a simple one  and it is about regular expression escaping  Do you have to escape a forward slash   in a regular expression  And how would you go about doing it

User · Accepted Answer

What context language   Some languages use   as the pattern delimiter  so yes  you need to escape it  depending on which language context   You escape it by putting a backward slash in front of it     For some languages  like PHP  you can use other characters as the delimiter and therefore you don t need to escape it  But AFAIK in all languages  the only special significance the   has is it may be the designated pattern delimiter

User · Answer

If the delimiter is    you will need to escape

User · Answer

Use the backslash   or choose a different delimiter  ie m   d  instead of    d   In Perl  you can change the   regular expression delimiter to almost any other special character if you preceed it with the letter m  for match

User · Answer

Here are a few options    In Perl  you can choose alternate delimiters   You re not confined to m     You could choose another  such as m     Then escaping isn t necessary   As a matter of fact  Damian Conway in  Perl Best Practices  asserts that m   is the only alternate delimiter that ought to be used  and this is reinforced by Perl  Critic  on CPAN    While you can get away with using a variety of alternate delimiter characters     and    seem to be the clearest to decipher later on   However  if either of those choices result in too much escaping  choose whichever one lends itself best to legibility   Common examples are m       m       and m       In cases where you either cannot or prefer not to use alternate delimiters  you can escape the forward slashes with a backslash   m           for example  using an alternate delimiter that could become m           which may read more clearly    Escaping the slash with a backslash is common enough to have earned a name and a wikipedia page  Leaning Toothpick Syndrome   In regular expressions where there s just a single instance  escaping a slash might not rise to the level of being considered a hindrance to legibility  but if it starts to get out of hand  and if your language permits alternate delimiters as Perl does  that would be the preferred solution

User · Answer

For java  you don t need to   eg            LOG    d                gt          LOG   d             If you put   in front of    IDE will tell you  Redundant Character Escape      in ReGex

User · Answer

If you are using C   you do not need to escape it

[regex] Escaping a forward slash in a regular expression

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