Regular Expressions 101

Save & Share

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

Flavor

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

Function

  • Match
  • Substitution
  • List
  • Unit Tests
/
(^(?:a|c|b[^c])+$)
/
mg
1st Capturing Group
(^(?:a|c|b[^c])+$)
^ asserts position at start of a line
Non-capturing group
(?:a|c|b[^c])+
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
1st Alternative
a
a matches the character a with index 9710 (6116 or 1418) literally (case sensitive)
2nd Alternative
c
c matches the character c with index 9910 (6316 or 1438) literally (case sensitive)
3rd Alternative
b[^c]
b matches the character b with index 9810 (6216 or 1428) literally (case sensitive)
Match a single character not present in the list below
[^c]
c matches the character c with index 9910 (6316 or 1438) literally (case sensitive)
$ asserts position at the end of a line
Global pattern flags
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
mg

Test String