Regular Expressions 101

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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

/
/
g

Test String

Code Generator

Language

Generated Code

use strict; my $str = ' <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>LCOV - .info.cleaned</title> <link rel="stylesheet" type="text/css" href="gcov.css"> </head> <body> <table width="100%" border=0 cellspacing=0 cellpadding=0> <tr><td class="title">LCOV - code coverage report</td></tr> <tr><td class="ruler"><img src="glass.png" width=3 height=3 alt=""></td></tr> <tr> <td width="100%"> <table cellpadding=1 border=0 width="100%"> <tr> <td width="10%" class="headerItem">Current view:</td> <td width="35%" class="headerValue">top level</td> <td width="5%"></td> <td width="15%"></td> <td width="10%" class="headerCovTableHead">Hit</td> <td width="10%" class="headerCovTableHead">Total</td> <td width="15%" class="headerCovTableHead">Coverage</td> </tr> <tr> <td class="headerItem">Test:</td> <td class="headerValue">.info.cleaned</td> <td></td> <td class="headerItem">Lines:</td> <td class="headerCovTableEntry">399</td> <td class="headerCovTableEntry">1019</td> <td class="headerCovTableEntryLo">39.2 %</td> </tr> <tr> <td class="headerItem">Date:</td> <td class="headerValue">2016-11-07</td> <td></td> <td class="headerItem">Functions:</td> <td class="headerCovTableEntry">22</td> <td class="headerCovTableEntry">67</td> <td class="headerCovTableEntryLo">32.8 %</td> </tr> <tr><td><img src="glass.png" width=3 height=3 alt=""></td></tr> </table> </td> </tr> <tr><td class="ruler"><img src="glass.png" width=3 height=3 alt=""></td></tr> </table> <center> <table width="80%" cellpadding=1 cellspacing=1 border=0> <tr> <td width="50%"><br></td> <td width="10%"></td> <td width="10%"></td> <td width="10%"></td>'; my $regex = qr/<(td) class="headerCovTableEntryLo">([0-9.]+)\s?%<\/\1>/p; 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