How to negate the whole regex

Question

I have a regex  for example  ma  t  1    It matches ma and t and doesn t match bla   I want to negate the regex  thus it must match bla and not ma and t  by adding something to this regex  I know I can write bla  the actual regex is however more complex

User · Answer

Assuming you only want to disallow strings that match the regex completely (i.e., mmbla is okay, but mm isn't), this is what you want:

^(?!(?:m{2}|t)$).*$

(?!(?:m{2}|t)$) is a negative lookahead; it says "starting from the current position, the next few characters are not mm or t, followed by the end of the string." The start anchor (^) at the beginning ensures that the lookahead is applied at the beginning of the string. If that succeeds, the .* goes ahead and consumes the string.

FYI, if you're using Java's matches() method, you don't really need the the ^ and the final $, but they don't do any harm. The $ inside the lookahead is required, though.

User · Answer

Apply this if you use laravel  Laravel has a not regex where field under validation must not match the given regular expression  uses the PHP preg match function internally   email    gt   not regex       i

User · Answer

b    w     ma  t  1    b  w     this is for the given regex  the  b is to find word boundary  the positive look ahead     w  is here to avoid spaces  the negative look ahead over the original regex is to prevent matches of it  and finally the   w   is to catch all the words that are left  the group that will hold the words is group 3  the simple    pattern  will not work as any sub-string will match the simple        m 2  t       will not work as it s granularity is full lines

User · Answer

Use negative lookaround     pattern   Positive lookarounds can be used to assert that a pattern matches  Negative lookarounds is the opposite  it s used to assert that a pattern DOES NOT match  Some flavor supports assertions  some puts limitations on lookbehind  etc   Links to regular-expressions info   Lookahead and Lookbehind Zero-Width Assertions Flavor comparison   See also   How do I convert CamelCase into human-readable names in Java  Regex for all strings not containing a string  A regex to match a substring that isn   t followed by a certain other substring    More examples  These are attempts to come up with regex solutions to toy problems as exercises  they should be educational if you re trying to learn the various ways you can use lookarounds  nesting them  using them to capture  etc     codingBat plusOut using regex codingBat repeatEnd using regex codingbat wordEnds using regex

[regex] How to negate the whole regex?

Examples related to regex

Examples related to regex-negation