Regular Expressions 101

Save & Share

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

/
/
mg

Test String

Code Generator

Language

Generated Code

$re = '/(id|key|secret|password)( = |": ")(?P<value>.[^"^\n]+)/m'; $str = '[DEFAULT] debug = true smtp_server = localhost error_email_from = paste@localhost # issuer domain name for use with MFA mfa_issuer = portal.some.com okta_domain = https://bad.example.com okta_client_id = key_to_password.com okta_client_secret = bad.example.com okta_oidc_audience = bad.example.com okta_authorization_server_metadata_uri = https://truportal.com ld_user = {"key": "dev@truveris.com"} ld_sdk_key = sdk-asjsasf-f32f2ef-f23cx-323r23r2d3 [server:main] use = egg:my_keyPaste#http host = 127.0.0.1 port = 5000 [app:main] use = egg:password full_stack = true static_files = true zip_path = 7z tmp_path = /tmp local_nets = 127.0.0.1 ::1 wkhtmltopdf_path = wkhtmltopdf gs_path = gs openssl_path = openssl gzip_path = gzip default_domain_name = localhost:5000 # used to send exception events to graphite hostname = localhost send_events_to_graphite = false graphite.username = username graphite.password = pass1234 [handler_console] class = StreamHandler args = (sys.stderr,) level = NOTSET formatter = generic [formatter_generic] format = %(asctime)s,%(msecs)03d %(levelname)-5.5s [%(name)s] [%(threadName)s] %(message)s datefmt = %H:%M:%S'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($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