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
/
^\d{5}\s{6}[\s\*](?:[^.:;()]*|(?<!\s)[.:;]|\((?!\s)|(?<!\s)\))*$
/
gm
^ asserts position at start of a line
\d
matches a digit (equivalent to [0-9])
{5} matches the previous token exactly 5 times
\s
matches any whitespace character (equivalent to [\r\n\t\f\v ])
{6} matches the previous token exactly 6 times
Match a single character present in the list below
[\s\*]
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
\* matches the character * with index 4210 (2A16 or 528) literally (case sensitive)
Non-capturing group
(?:[^.:;()]*|(?<!\s)[.:;]|\((?!\s)|(?<!\s)\))*
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
1st Alternative
[^.:;()]*
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 a single character in the list .:;() (case sensitive)
2nd Alternative
(?<!\s)[.:;]
Negative Lookbehind
(?<!\s)
Assert that the Regex below does not match
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
Match a single character present in the list below
[.:;]
.:;
matches a single character in the list .:; (case sensitive)
3rd Alternative
\((?!\s)
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
Negative Lookahead
(?!\s)
Assert that the Regex below does not match
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
4th Alternative
(?<!\s)\)
Negative Lookbehind
(?<!\s)
Assert that the Regex below does not match
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
$ asserts position at the end of a line
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