Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

/
/

Test String

Code Generator

Language

Generated Code

const regex = /(\{\".*?:.*?\"\})/; // Alternative syntax using RegExp constructor // const regex = new RegExp('(\\{\\".*?:.*?\\"\\})', '') const str = `<font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1' cellspacing='0' cellpadding='1'> <tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Notice: Undefined index: in C:\\wamp\\www\\form.php on line <i>464</i></th></tr> <tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr> <tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr> <tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0008</td><td bgcolor='#eeeeec' align='right'>274560</td><td bgcolor='#eeeeec'>{main}( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor='#eeeeec' align='center'>2</td><td bgcolor='#eeeeec' align='center'>0.8826</td><td bgcolor='#eeeeec' align='right'>38298888</td><td bgcolor='#eeeeec'>do_action( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor='#eeeeec' align='center'>3</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300392</td><td bgcolor='#eeeeec'><a href='http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}' target='_new'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>4</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300560</td><td bgcolor='#eeeeec'>Example_Post->ajax_Example_posting_form( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>5</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38301552</td><td bgcolor='#eeeeec'>Example_Post->Example_form_submitting( )</td><td title='C:\\wamp\\www\\form.php' bgcolor='#eeeeec'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font> <br /> <font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1' cellspacing='0' cellpadding='1'> <tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Notice: Undefined index: name in C:\\wamp\\www\\form.php on line <i>475</i></th></tr> <tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr> <tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr> <tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0008</td><td bgcolor='#eeeeec' align='right'>274560</td><td bgcolor='#eeeeec'>{main}( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor='#eeeeec' align='center'>2</td><td bgcolor='#eeeeec' align='center'>0.8826</td><td bgcolor='#eeeeec' align='right'>38298888</td><td bgcolor='#eeeeec'>do_action( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor='#eeeeec' align='center'>3</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300392</td><td bgcolor='#eeeeec'><a href='http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}' target='_new'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>4</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300560</td><td bgcolor='#eeeeec'>Example_Post->ajax_Example_posting_form( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>5</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38301552</td><td bgcolor='#eeeeec'>Example_Post->Example_form_submitting( )</td><td title='C:\\wamp\\www\\form.php' bgcolor='#eeeeec'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font> {"redirect_to":"false","show_message":true,"message":"<div class=\\"notification alert-success\\"><p>Post updated successfully<\\/p><a href=\\"#\\" class=\\"close-btn\\">\\u00d7<\\/a><\\/div><br \\/>"} <font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1' cellspacing='0' cellpadding='1'> <tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Notice: Undefined index: in C:\\wamp\\www\\form.php on line <i>464</i></th></tr> <tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr> <tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr> <tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0008</td><td bgcolor='#eeeeec' align='right'>274560</td><td bgcolor='#eeeeec'>{main}( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor='#eeeeec' align='center'>2</td><td bgcolor='#eeeeec' align='center'>0.8826</td><td bgcolor='#eeeeec' align='right'>38298888</td><td bgcolor='#eeeeec'>do_action( )</td><td title='C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php' bgcolor='#eeeeec'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor='#eeeeec' align='center'>3</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300392</td><td bgcolor='#eeeeec'><a href='http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}' target='_new'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>4</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38300560</td><td bgcolor='#eeeeec'>Example_Post->ajax_Example_posting_form( )</td><td title='C:\\wamp\\www\\Example\\wp-includes\\plugin.php' bgcolor='#eeeeec'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor='#eeeeec' align='center'>5</td><td bgcolor='#eeeeec' align='center'>0.8827</td><td bgcolor='#eeeeec' align='right'>38301552</td><td bgcolor='#eeeeec'>Example_Post->Example_form_submitting( )</td><td title='C:\\wamp\\www\\form.php' bgcolor='#eeeeec'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font>`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // 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