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

/
/
Ui

Test String

Code Generator

Language

Generated Code

use strict; my $str = '<a style="display:block;" href="javascript:void(0);" onclick="expandImageRotate ( \'xImage_56362441\',\'http://snpi.dell.com/snp/images/products/large/en-th~370-ACMK/370-ACMK.jpg\',event,this,\'\' );"><img id="xImage_56362441_sm_Image" border="0" alt="Dell 8 GB Certified Replacement Memory Module for Select Dell Systems- UDIMM ECC" title="Dell 8 GB Certified Replacement Memory Module for Select Dell Systems- UDIMM ECC" width="200" src="http://snpi.dell.com/snp/images/products/mlrg/en-th~370-ACMK/370-ACMK.jpg" z></a> </span></td></tr> <tr><td colspan="2" style="padding: 15px 0px 5px 0px"><table cellpadding="4" cellspacing="0" align="center" border="0"><tr class="thumbnailRow"><td align="center"><table cellpadding="0" cellspacing="0" border="0"> <tr> <td><img src="http://i.dell.com/images/global/brand/ui/top_left_small.gif" width="3" height="3"></td> <td width="100%"><img src="http://i.dell.com/images/global/brand/ui/top_horiz_small.gif" width="100%" height="3" border="0"></td> <td class="rightAlign"><img src="http://i.dell.com/images/global/brand/ui/top_right_small.gif" width="3" height="3"></td> </tr> <tr> <td class="leftVertSmall"></td> <td><span style="display:inline-block;width:40px;"> <script type="text/javascript"> RegisterImage(\'original_image\', \'http://snpi.dell.com/snp/images/products/mlrg/en-th~370-ACMK/370-ACMK.jpg\', \'http://snpi.dell.com/snp/images/products/large/en-th~370-ACMK/370-ACMK.jpg\', "Dell 8 GB Certified Replacement Memory Module for Select Dell Systems- UDIMM ECC", \'xImage_18637405\', \'\'); </script><div style="position: absolute; top: 0pt; left: 0pt;" id="xImage_18637405_container"></div>'; my $regex = qr/([a-z\-_0-9\/\:\.]*\.(jpg|jpeg|png|gif))/ip; 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