Which regular expression operator means Don t match this character

Question

characters all mean match this character  Which character means  don t  match this  Examples would help

User · Accepted Answer

You can use negated character classes to exclude certain characters: for example [^abcde] will match anything but a,b,c,d,e characters.

Instead of specifying all the characters literally, you can use shorthands inside character classes: [\w] (lowercase) will match any "word character" (letter, numbers and underscore), [\W] (uppercase) will match anything but word characters; similarly, [\d] will match the 0-9 digits while [\D] matches anything but the 0-9 digits, and so on.

If you use PHP you can take a look at the regex character classes documentation.

User · Answer

used at the beginning of a character range  or negative lookahead lookbehind assertions    gt  gt  gt  re match    f     foo    gt  gt  gt  re match    f     bar    lt  sre SRE Match object at 0x7f8b102ad6b0 gt   gt  gt  gt  re match     foo        foo    gt  gt  gt  re match     foo        bar    lt  sre SRE Match object at 0x7f8b0fe70780 gt

User · Answer

There s two ways to say  don t match   character ranges  and zero-width negative lookahead lookbehind   The former  don t match a  b  c or 0    a-c0   The latter  match any three-letter string except foo and bar      foo bar   3   or    3    lt  foo bar   Also  a correction for you       and   do not actually match anything  They are repetition operators  and always follow a matching operator  Thus  a  means match one or more of a   a-c0   means match one or more of a  b  c or 0  while   a-c0   would match one or more of anything that wasn t a  b  c or 0

User · Answer

within       is negation in regular expression whereas   is  begining of string     a-z   matches any single character that is not from  a  to  z     a-z  means string starts with from  a  to  z    Reference

[regex] Which regular expression operator means 'Don't' match this character?

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