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
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /\[15-Nov\-2019 [\d:]+ UTC\] PHP Notice: wpdb::prepare was called <strong>incorrectly<\/strong>\. The query does not contain the correct number of placeholders \(0\) for the number of arguments passed \(1\)\. Please see <a href="https:\/\/wordpress\.org\/support\/article\/debugging-in-wordpress\/">Debugging in WordPress<\/a> for more information\. \(This message was added in version 4\.8\.3\.\) in \/var\/www\/html\/blog\.nssl\.noaa\.gov\/wp-includes\/functions\.php on line 4903/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\[15-Nov\\-2019 [\\d:]+ UTC\\] PHP Notice: wpdb::prepare was called <strong>incorrectly<\\\/strong>\\. The query does not contain the correct number of placeholders \\(0\\) for the number of arguments passed \\(1\\)\\. Please see <a href="https:\\\/\\\/wordpress\\.org\\\/support\\\/article\\\/debugging-in-wordpress\\\/">Debugging in WordPress<\\\/a> for more information\\. \\(This message was added in version 4\\.8\\.3\\.\\) in \\\/var\\\/www\\\/html\\\/blog\\.nssl\\.noaa\\.gov\\\/wp-includes\\\/functions\\.php on line 4903', 'gm') const str = `[15-Nov-2019 06:00:01 UTC] PHP Notice: wpdb::prepare was called <strong>incorrectly</strong>. The query does not contain the correct number of placeholders (0) for the number of arguments passed (1). Please see <a href="https://wordpress.org/support/article/debugging-in-wordpress/">Debugging in WordPress</a> for more information. (This message was added in version 4.8.3.) in /var/www/html/blog.nssl.noaa.gov/wp-includes/functions.php on line 4903`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions