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
/
<\?[\s\S]*?(?:\z|\?\>)
/
gm
< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
\? matches the character ? with index 6310 (3F16 or 778) literally (case sensitive)
Match a single character present in the list below
[\s\S]
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
\S matches any non-whitespace character (equivalent to [^\r\n\t\f\v ])
Non-capturing group
(?:\z|\?\>)
1st Alternative
\z
\z asserts position at the end of the string
2nd Alternative
\?\>
\? matches the character ? with index 6310 (3F16 or 778) literally (case sensitive)
\> matches the character > with index 6210 (3E16 or 768) 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)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String