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

/
/
gm

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"^(?:[^>\n]*>){2}\w+\s+\w+\d+\=(?P<cs_details>\w+[ -])" test_str = ("Jan 29 06:32:56 172.16.23.26 Jan 29 06:30:27 : CEF:0|ABCD Networks|NAC-VM-C|8.6.2.1203|-1|IP Address Update|1|rt=Jan 29 06:30:27 877 EST cat=EndStation src=10.10.14.58 smac=FA:39:71:6F:B3:43 shost=iPhone cs1Label=Physical<space>network<space>location cs1=AMNYPARU535A-FL37-VIP ROLE mobile msg=Adapter FA:39:71:6F:B3:43 IP Address changed from 10.10.14.53 to 10.10.14.58\n\n" "Jan 28 21:22:51 172.16.23.26 Jan 28 21:20:24 : CEF:0|ABCD Networks|FortiNAC-VM-C|8.6.2.1203|-1|IP Address Update|1|rt=Jan 28 21:20:24 110 EST cat=EndStation src=10.3.38.61 smac=EA:19:49:37:10:73 shost=TsutomunoiPhone cs1Label=Physical<space>network<space>location cs1=APTOKARU535A-VIP ROLE mobile msg=Adapter EA:19:49:37:10:73 IP Address changed from 100.64.241.38 to 10.3.38.61\n\n" "Jan 29 10:52:59 172.16.23.26 Jan 29 10:50:30 : CEF:0|ABCD Networks|NAC-VM-C|8.6.2.1203|303067011|Rogue Connected|1|rt=Jan 29 10:50:30 523 EST cat=EndStation smac=42:DE:D8:19:D2:69 cs1Label=Physical<space>network<space>location cs1=EUPARARU535A [10.2.32.198]-VIP ROLE registration msg=Rogue Host 42:DE:D8:19:D2:69 Connected to EUPARARU535A [10.2.32.198]-VIP ROLE registration.") matches = re.finditer(regex, test_str, re.MULTILINE) 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