Invert match with regexp

Question

With PCRE  how can you construct an expression that will only match if a string is not found     If I were using grep  which I m not  I would want the -v option   A more concrete example   I want my regexp to match iff string foo is not in the string   So it would match bar would but not foobar

User · Answer

You can also do this  in python  by using re split  and splitting based on your regular expression  thus returning all the parts that don t match the regex  splitting based on what doesn t match a regularexpression

User · Answer

Build an expression that matches  and use  match       logical negation  That s probably how grep does anyway

User · Answer

It s indeed almost a duplicate  I guess the regex you re looking for is     foo

User · Answer

Okay  I have refined my regular expression based on the solution you came up with  which erroneously matches strings that start with  test          foo        This regular expression will match only strings that do not contain foo  The first lookahead will deny strings beginning with  foo   and the second will make sure that foo isn t found elsewhere in the string

User · Answer

Based on Daniel s answer  I think I ve got something that works         test       The key is that you need to make the negative assertion on every character in the string

[regex] Invert match with regexp

Examples related to regex

Examples related to pcre