Regular Expressions 101

@regex101
Donate
Sponsor
Contact
Bug Reports & Feedback
Wiki
Whats new?

Save & Share

  • Save Regex
    ctrl+s
  • Update Regex
    ctrl+⇧+s

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python 2.7
  • Golang
  • Java 8

Function

  • Match
  • Substitution
  • List
  • Unit Tests
/
<!--(?>[^-<>])(?>(?!-->)[-<>][^-<>])*-->
/
gms
<!-- matches the characters <!-- literally (case sensitive)
Atomic Group
(?>[^-<>])
Non-capturing group that discards backtracking positions once matched.
Match a single character not present in the list below
[^-<>]
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
- matches the character - literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
<> matches a single character in the list <> (case sensitive)
Atomic Group
(?>(?!-->)[-<>][^-<>])*
Non-capturing group that discards backtracking positions once matched.
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Negative Lookahead
(?!-->)
Assert that the Regex below does not match
--> matches the characters --> literally (case sensitive)
Match a single character present in the list below
[-<>]
- matches the character - literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
<> matches a single character in the list <> (case sensitive)
Match a single character not present in the list below
[^-<>]
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
- matches the character - literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
<> matches a single character in the list <> (case sensitive)
--> matches the characters --> literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
s modifier: single line. Dot matches newline characters
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gms

Test String

Substitution

Processing...

Regex Debugger

Please wait while your expression is being debugged...