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

r"
"
gm

Test String

Code Generator

Language

Generated Code

use strict; my $str = '2.177.12.140 - - [22/Jan/2019:03:56:36 +0330] "GET /m/filter/b1,b103 HTTP/1.1" 200 4911 "https://www.zanbil.ir/m/product/33606/%D8%AA%D9%84%D9%88%DB%8C%D8%B2%DB%8C%D9%88%D9%86-%D8%A7%D9%84-%D8%A7%DB%8C-%D8%AF%DB%8C-%D8%B3%D8%A7%D9%85%D8%B3%D9%88%D9%86%DA%AF-%D9%85%D8%AF%D9%84-55NU8950-Ultra-HD-4K" "Mozilla/5.0 (Android 7.1.1; Mobile; rv:64.0) Gecko/64.0 Firefox/64.0" "-"'; my $regex = qr/([\d.]*) . . \[([\w/]*):([\w:]*) [\+\w]*] \"[\w]* [\W\w\s]* *\"*(www.*\w*.*\w{2})* [\w\W]*\" (\w*) (\w*) \"[\w\W]*(https://www\.\w*\.\w{2})[\W][^\s]* *\" *\"([^\s]*) [(\W\w]([\w\W)]*)\) *([^\"]*)\)*[\w]*.*/mp; if ( $str =~ /$regex/g ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html