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

/
/
imsg

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"(?<=^|;|<\?php\s|<\?\s)(\s*?)(\h*define\s*\(\s*[\'\"](\w*?)[\'\"]\s*)(,\s*([\'\"].*?[\'\"]|.*?)\s*)((?:,\s*(?:true|false)\s*)?\)\s*;)" test_str = ("<?php\n" "/**\n" " * The base configuration for WordPress\n" " *\n" " * The wp-config.php creation script uses this file during the\n" " * installation. You don't have to use the web site, you can\n" " * copy this file to \"wp-config.php\" and fill in the values.\n" " *\n" " * This file contains the following configurations:\n" " *\n" " * * MySQL settings\n" " * * Secret keys\n" " * * Database table prefix\n" " * * ABSPATH\n" " *\n" " * @link https://codex.wordpress.org/Editing_wp-config.php\n" " *\n" " * @package WordPress\n" " */\n\n" "// ** MySQL settings - You can get this info from your web host ** //\n" "/** The name of the database for WordPress */\n" "define('DB_NAME', 'database_name_here');\n\n" "/** MySQL database username */\n" "define('DB_USER', 'username_here');\n\n" "/** MySQL database password */\n" "define('DB_PASSWORD', 'password_here');\n\n" "/** MySQL hostname */\n" "define('DB_HOST', 'localhost');\n\n" "/** Database Charset to use in creating database tables. */\n" "define('DB_CHARSET', 'utf8');\n\n" "/** The Database Collate type. Don't change this if in doubt. */\n" "define('DB_COLLATE', '');\n\n" "/**#@+\n" " * Authentication Unique Keys and Salts.\n" " *\n" " * Change these to different unique phrases!\n" " * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}\n" " * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.\n" " *\n" " * @since 2.6.0\n" " */\n" "define('AUTH_KEY', 'put your unique phrase here');\n" "define('SECURE_AUTH_KEY', 'put your unique phrase here');\n" "define('LOGGED_IN_KEY', 'put your unique phrase here');\n" "define('NONCE_KEY', 'put your unique phrase here');\n" "define('AUTH_SALT', 'put your unique phrase here');\n" "define('SECURE_AUTH_SALT', 'put your unique phrase here');\n" "define('LOGGED_IN_SALT', 'put your unique phrase here');\n" "define('NONCE_SALT', 'put your unique phrase here');\n\n" "/**#@-*/\n\n" "/**\n" " * WordPress Database Table prefix.\n" " *\n" " * You can have multiple installations in one database if you give each\n" " * a unique prefix. Only numbers, letters, and underscores please!\n" " */\n" "$table_prefix = 'wp_';\n\n" "/**\n" " * For developers: WordPress debugging mode.\n" " *\n" " * Change this to true to enable the display of notices during development.\n" " * It is strongly recommended that plugin and theme developers use WP_DEBUG\n" " * in their development environments.\n" " *\n" " * For information on other constants that can be used for debugging,\n" " * visit the Codex.\n" " *\n" " * @link https://codex.wordpress.org/Debugging_in_WordPress\n" " */\n" "define('WP_DEBUG', false);\n\n" "//define( 'TEST_UPDATE_NO_MATCH', 'updateme' );\n" "// define( 'TEST_UPDATE_NO_MATCH', 'updateme' );\n\n" "define( 'TEST_MULTIPLE_LINE_1', 'update);me' );define( 'TEST_MULTIPLE_LINE_2', 'updateme' ); define( 'TEST_MULTIPLE_LINE_3', 'updateme' );\n\n" "define( 'TEST_UPDATE_1', 'updateme' );\n" "define( 'TEST_UPDATE_2' , 'updateme' );\n" "define(\n" " 'TEST_UPDATE_3',\n" " 'updateme'\n" ");\n" "define(\n" " 'TEST_UPDATE_4'\n" " ,\n" " 'updateme'\n" " )\n" ";\n" " define (\n" " 'TEST_UPDATE_5'\n" ",\n" " 'updateme'\n" ")\n" " ;\n" "define( \"TEST_UPDATE_6\",'updateme' );\n" "define ( \"TEST_UPDATE_7\",'updateme' );\n" "define('TEST_UPDATE_8','updateme');\n" "DEFINE( 'TEST_UPDATE_9', 'updateme' );\n" "DEFINE ('TEST_UPDATE_10' ,'updateme' );\n" "define( 'TEST_UPDATE_11', 'updateme', false );\n" "define( 'TEST_UPDATE_12' , 'updateme' , false );\n" "define(\n" " 'TEST_UPDATE_13',\n" " 'updateme',\n" " false\n" ");\n" "define(\n" " 'TEST_UPDATE_14'\n" " ,\n" " 'updateme',\n" " false\n" " )\n" ";\n" " define (\n" " 'TEST_UPDATE_15'\n" ",\n" " 'updateme'\n" " ,\n" "false\n" ")\n" " ;\n" "define( \"TEST_UPDATE_16\",'updateme' ,false );\n" "define ( \"TEST_UPDATE_17\",'updateme',false );\n" "define('TEST_UPDATE_18','updateme',false);\n" "DEFINE('TEST_UPDATE_19', 'updateme', false);\n" "DEFINE ('TEST_UPDATE_20' ,'updateme' ,false );\n\n" "/* That's all, stop editing! Happy blogging. */\n\n" "/** Absolute path to the WordPress directory. */\n" "if ( !defined('ABSPATH') )\n" " define('ABSPATH', dirname(__FILE__) . '/');\n\n" "/** Sets up WordPress vars and included files. */\n" "require_once(ABSPATH . 'wp-settings.php');\n") matches = re.finditer(regex, test_str, re.IGNORECASE | re.MULTILINE | re.DOTALL) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html