Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

~
~
ixmXs

Test String

Code Generator

Generated Code

$re = '~(?(DEFINE) (?<prepend> (?> \s++ | #multi-line comment by Jeffrey Friedl (fastest) /\* [^*]* \*+ (?:[^*/][^*]*\*+)* / | ;++ )*+ ) #https://www.postgresql.org/docs/11/sql-commands.html (?<command>abort|alter|begin|cache|call|checkpoint|cluster|comment|commit|copy|create|deallocate|delete|discard|do|drop|execute|flush|grant|import\s++foreign\s++schema|insert|kill|load|lock|prepare|prepare\s++transaction|reassign\s++owned|refresh\s++materialized\s++view|release\s++savepoint|rename|replace|reset|revoke|rollback|select\s++into|set\s++constraints|start\s++transaction|truncate|update) ) ^ (?&prepend) \K (?&command) \b (?! (?&prepend) \( #REPLACE() function can be similar to command )~ixmXs'; $str = 'WITH t1 AS ( -- UPDATE /* INSERT */ SELECT * FROM t WHERE s = REPLACE(s, \'a\', \'b\') ), t2 AS ( -- комментарий UPDATE /* INSERT */UPDATE-- * FROM t SET i = 1 RETURNING * ), INSERT b SELECT * FROM t2'; preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0); // Print the entire match result var_dump($matches);

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