Regular Expressions 101

Save & Manage Regex

  • Current Version: 2
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
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
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r"(?<!-)(?:[0-9a-f]{2}[:-]){5}[0-9a-f]{2}(?!-)", flags=re.IGNORECASE) test_str = ("Windows IP Configuration\n\n" " Host Name . . . . . . . . . . . . : CheziAndSima-PC\n" " Primary Dns Suffix . . . . . . . : \n" " Node Type . . . . . . . . . . . . : Hybrid\n" " IP Routing Enabled. . . . . . . . : No\n" " WINS Proxy Enabled. . . . . . . . : No\n" " DNS Suffix Search List. . . . . . : kramer.local\n\n" "Ethernet adapter Local Area Connection:\n\n" " Connection-specific DNS Suffix . : \n" " Description . . . . . . . . . . . : Atheros AR8151 PCI-E Gigabit Ethernet Controller (NDIS 6.20)\n" " Physical Address. . . . . . . . . : 50-E5-49-CE-FC-EF\n" " DHCP Enabled. . . . . . . . . . . : Yes\n" " Autoconfiguration Enabled . . . . : Yes\n" " Link-local IPv6 Address . . . . . : fe80::5cba:e9f2:a99f:4499%11(Preferred) \n" " IPv4 Address. . . . . . . . . . . : 10.0.0.1(Preferred) \n" " Subnet Mask . . . . . . . . . . . : 255.255.255.0\n" " Lease Obtained. . . . . . . . . . : ™š 06 €…‚…‘ˆ 2016 20:35:49\n" " Lease Expires . . . . . . . . . . : ‰…™Œ‰™‰ 09 €…‚…‘ˆ 2016 21:05:49\n" " Default Gateway . . . . . . . . . : 10.0.0.138\n" " DHCP Server . . . . . . . . . . . : 10.0.0.138\n" " DHCPv6 IAID . . . . . . . . . . . : 240182601\n" " DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-7A-1F-FC-50-E5-49-CE-FC-EF\n" " DNS Servers . . . . . . . . . . . : 10.0.0.138\n" " NetBIOS over Tcpip. . . . . . . . : Enabled\n\n" "Ethernet adapter Local Area Connection* 11:\n\n" " Connection-specific DNS Suffix . : kramer.local\n" " Description . . . . . . . . . . . : Juniper Networks Virtual Adapter\n" " Physical Address. . . . . . . . . : 02-05-85-7F-EB-80\n" " DHCP Enabled. . . . . . . . . . . : No\n" " Autoconfiguration Enabled . . . . : Yes\n" " Link-local IPv6 Address . . . . . : fe80::8dfb:6d42:97e1:2dc7%19(Preferred) \n" " IPv4 Address. . . . . . . . . . . : 172.16.2.7(Preferred) \n" " Subnet Mask . . . . . . . . . . . : 255.255.255.255\n" " Default Gateway . . . . . . . . . : \n" " DHCPv6 IAID . . . . . . . . . . . : 436340101\n" " DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-7A-1F-FC-50-E5-49-CE-FC-EF\n" " DNS Servers . . . . . . . . . . . : 172.16.0.6\n" " 172.16.0.91\n" " NetBIOS over Tcpip. . . . . . . . : Enabled\n\n" "Tunnel adapter isatap.{899E5284-7FD6-4831-B397-9BA931E543E1}:\n\n" " Media State . . . . . . . . . . . : Media disconnected\n" " Connection-specific DNS Suffix . : \n" " Description . . . . . . . . . . . : Microsoft ISATAP Adapter\n" " Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0\n" " DHCP Enabled. . . . . . . . . . . : No\n" " Autoconfiguration Enabled . . . . : Yes\n\n" "Tunnel adapter Teredo Tunneling Pseudo-Interface:\n\n" " Media State . . . . . . . . . . . : Media disconnected\n" " Connection-specific DNS Suffix . : \n" " Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface\n" " Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0\n" " DHCP Enabled. . . . . . . . . . . : No\n" " Autoconfiguration Enabled . . . . : Yes\n\n" "Tunnel adapter isatap.kramer.local:\n\n" " Media State . . . . . . . . . . . : Media disconnected\n" " Connection-specific DNS Suffix . : kramer.local\n" " Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2\n" " Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0\n" " DHCP Enabled. . . . . . . . . . . : No\n" " Autoconfiguration Enabled . . . . : Yes\n") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

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