Regular Expressions 101

Save & Share

Flavor

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

Function

  • Match
  • Substitution
  • List
  • Unit Tests
/
^(?=.*\baxis)(?=.*\bregular)(?=.*\bbluechip)
/
gmi
^ asserts position at start of a line
Positive Lookahead
(?=.*\baxis)
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\b assert position at a word boundary: (^\w|\w$|\W\w|\w\W)
axis
matches the characters axis literally (case insensitive)
Positive Lookahead
(?=.*\bregular)
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\b assert position at a word boundary: (^\w|\w$|\W\w|\w\W)
regular
matches the characters regular literally (case insensitive)
Positive Lookahead
(?=.*\bbluechip)
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\b assert position at a word boundary: (^\w|\w$|\W\w|\w\W)
bluechip
matches the characters bluechip literally (case insensitive)
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)
i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/
gmi

Test String

Code Generator

Generated Code

Loading code sample...
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report.
For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php