正则表达式：匹配除特定模式以外的所有内容

Question

I need a regular expression able to match everything but a string starting with a specific pattern (specifically index.php and what follows, like index.php?id=2342343 ).

Answer 1

Regex: match everything but :

• a string starting with a specific pattern (eg any - empty, too - string not starting with foo ):
  • Lookahead-based solution for NFAs:
    • ^(?!foo).*$
    • ^(?!foo)
• Negated character class based solution for regex engines not supporting lookarounds :
  • ^(([^f].{2}|.[^o].|.{2}[^o]).*|.{0,2})$
  • ^([^f].{2}|.[^o].|.{2}[^o])|^.{0,2}$
• a string ending with a specific pattern (say, no world. at the end):
  • Lookbehind-based solution:
    • (?<!world\\.)$
    • ^.*(?<!world\\.)$
  • Lookahead solution:
    • ^(?!.*world\\.$).*
    • ^(?!.*world\\.$)
  • POSIX workaround:
    • ^(.*([^w].{5}|.[^o].{4}|.{2}[^r].{3}|.{3}[^l].{2}|.{4}[^d].|.{5}[^.])|.{0,5})$
    • ([^w].{5}|.[^o].{4}|.{2}[^r].{3}|.{3}[^l].{2}|.{4}[^d].|.{5}[^.]$|^.{0,5})$
• a string containing specific text (say, not match a string having foo ):
  • Lookaround-based solution:
    • ^(?!.*foo)
    • ^(?!.*foo).*$
  • POSIX workaround:
    • Use the online regex generator at www.formauri.es/personal/pgimeno/misc/non-match-regex
• a string containing specific character (say, avoid matching a string having a | symbol):
  • ^[^|]*$
• a string equal to some string (say, not equal to foo ):
  • Lookaround-based:
    • ^(?!foo$)
    • ^(?!foo$).*$
  • POSIX:
    • ^(.{0,2}|.{4,}|[^f]..|.[^o].|..[^o])$
• a sequence of characters :
  • PCRE (match any text but cat ): /cat(*SKIP)(*FAIL)|[^c]*(?:c(?!at)[^c]*)*/i or /cat(*SKIP)(*FAIL)|(?:(?!cat).)+/is
  • Other engines allowing lookarounds: (cat)|[^c]*(?:c(?!at)[^c]*)* (or (?s)(cat)|(?:(?!cat).)* , or (cat)|[^c]+(?:c(?!at)[^c]*)*|(?:c(?!at)[^c]*)+[^c]* ) and then check with language means: if Group 1 matched, it is not what we need, else, grab the match value if not empty
• a certain single character or a set of characters :
  • Use a negated character class : [^az]+ (any char other than a lowercase ASCII letter)
  • Matching any char(s) but | : [^|]+

Demo note : the newline \\n is used inside negated character classes in demos to avoid match overflow to the neighboring line(s). They are not necessary when testing individual strings.

Anchor note : In many languages, use \\A to define the unambiguous start of string, and \\z (in Python, it is \\Z , in JavaScript, $ is OK) to define the very end of the string.

Dot note : In many flavors (but not POSIX, TRE, TCL), . matches any char but a newline char. Make sure you use a corresponding DOTALL modifier ( /s in PCRE/Boost/.NET/Python/Java and /m in Ruby) for the . to match any char including a newline.

Backslash note : In languages where you have to declare patterns with C strings allowing escape sequences (like \\n for a newline), you need to double the backslashes escaping special characters so that the engine could treat them as literal characters (eg in Java, world\\. will be declared as "world\\\\." , or use a character class: "world[.]" ). Use raw string literals (Python r'\\bworld\\b' ), C# verbatim string literals @"world\\." , or slashy strings/regex literal notations like /world\\./ .

Answer 2

不是正则表达式专家，但我认为您可以从一开始就使用负前瞻，例如^(?!foo).*$不应匹配以foo开头的任何内容。

Answer 3

You can put a ^ in the beginning of a character set to match anything but those characters.

[^=]*

will match everything but =

Answer 4

只需匹配/^index\\.php/然后拒绝匹配它的任何内容。

Answer 5

In python:

>>> import re
>>> p='^(?!index\.php\?[0-9]+).*$'
>>> s1='index.php?12345'
>>> re.match(p,s1)
>>> s2='index.html?12345'
>>> re.match(p,s2)
<_sre.SRE_Match object at 0xb7d65fa8>

Answer 6

I need a regex able to match everything but except a string starting with index.php a specific pattern (specifically index.php and what follows, like index.php?id=2342343)

Use method Exec

 let match, arr = [], myRe = /([\\s\\S]+?)(?:index\\.php\\?id.+)/g; var str = 'http://regular-viragenia/index.php?id=2342343'; while ((match = myRe.exec(str)) != null) { arr.push(match[1]); } console.log(arr);

 var myRe = /([\\s\\S]+?)(?:index\\.php\\?id=.+)/g; var str = 'http://regular-viragenia/index.php?id=2342343'; var matches_array = myRe.exec(str); console.log(matches_array[1]);

OR OTHER MATCH

 let match, arr = [], myRe = /index.php\\?id=((?:(?!index)[\\s\\S])*)/g; var str = 'http://regular-viragenia/index.php?id=2342343index.php?id=111index.php?id=222'; while ((match = myRe.exec(str)) != null) { arr.push(match[1]); } console.log(arr);

Answer 7

I had this problem for multiple search and replace. Needed a negative pattern to skip matching till the next search

import re

text = "alex ![image]dfsf(dfd.png) [image]fsdf(dfd.png) home ![image]fdsf(dfd.png) end"
replaced_text = re.sub(r'!\[image\](.*)\(.*\.png\)', '*', text)
print(replaced_text)

gave

alex * end

basically, the middle was swallowing till the next .png

Used the method https://stackoverflow.com/a/17761124/429476 by Firish and got what I wanted. Here the character space is not matched; and the next words are separated by space

replaced_text = re.sub(r'!\[image\]([^ ]*)\([^ ]*\.png\)', '*', text)

and got what I wanted

alex * [image]fsdf(dfd.png) home * end

Answer 8

grep -v in shell

!~ in perl

Please add more in other languages - I marked this as Community Wiki.

Answer 9

How about not using regex:

// In PHP
0 !== strpos($string, 'index.php')