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

/
/
is

Test String

Code Generator

Language

Generated Code

use strict; my $str = '<div id="tmm-grid-swatch-HARDCOVER" class="a-column a-span6 a-text-left swatchElement selected celwidget" role="listitem" data-csa-c-id="rqzqyx-arj8qg-jifnrc-pelgtz" data-cel-widget="tmm-grid-swatch-HARDCOVER"> <span class="a-button a-button-selected a-spacing-none a-button-toggle format" id="a-autoid-2"><span class="a-button-inner"><a href="javascript:void(0)" role="radio" aria-checked="true" aria-current="page" class="a-button-text a-text-left" id="a-autoid-2-announce"> <span class="slot-title"> <span aria-label="Hardcover Format:">Hardcover</span> <br> </span> <span class="slot-price"> <span aria-label="$16.94" class="a-size-base a-color-price a-color-price"> $16.94 </span> </span> <br id="sw-slots-grid-line-break"> </a></span></span> </div>'; my $regex = qr/<a href="javascript:void\(0\)"[^>]*>(.*?)id="sw-slots-grid-line-break"/isp; if ( $str =~ /$regex/ ) { 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