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

r"
"
gm

Test String

Code Generator

Language

Generated Code

use strict; my $str = '<head><title>Popular Baby Names</title> <meta name="dc.language" scheme="ISO639-2" content="eng"> <meta name="dc.creator" content="OACT"> <meta name="lead_content_manager" content="JeffK"> <meta name="coder" content="JeffK"> <meta name="dc.date.reviewed" scheme="ISO8601" content="2006-03-10"> <link rel="stylesheet" href="../OACT/templatefiles/master.css" type="text/css" media="screen"> <link rel="stylesheet" href="../OACT/templatefiles/print.css" type="text/css" media="print"> </head> <body bgcolor="#ffffff" text="#000000" topmargin="1" leftmargin="0"> <table width="100%" border="0" cellspacing="0" cellpadding="4"> <tbody> <tr> <td class="sstop" valign="bottom" align="left" width="25%"> Social Security Online </td> <td valign="bottom" class="titletext"> <!-- sitetitle -->Popular Baby Names </td> </tr> <tr bgcolor="#333366"><td colspan="2" height="1"></td></tr> <tr> <td class="graystars" width="25%" valign="top"> <a href="../OACT/babynames/">Popular Baby Names</a></td> <td valign="top"> <a href="http://www.ssa.gov/"><img src="/templateimages/tinylogo.gif" width="52" height="47" align="left" alt="SSA logo: link to Social Security home page" border="0"></a> <h1>Popular Names by Birth Year</h1>September 11, 2014</td> </tr> </tbody></table> <script type="text/javascript" src="../OACT/babynames/chkinput.js"></script> <table width="100%" border="0" cellspacing="0" cellpadding="4" summary="formatting"> <tr valign="top"> <td width="25%" class="greycell"> <a href="../OACT/babynames/background.html">Background information</a> <p><br /> &nbsp; Select another <label for="yob">year of birth</label>?<br /> <form name="popnames" method="post" action="/cgi-bin/popularnames.cgi" onSubmit="return submitIt();"> &nbsp; <input type="text" name="year" id="yob" size="4" value="2012"><input type="hidden" name="top" value="25"><input type="hidden" name="number" value=""> &nbsp; <input type="submit" value=" Go "></form> </td> <td><p align="center"><table width="$tablewidth" border="1" bordercolor="#aaabbb" cellpadding="2" cellspacing="0" summary="Popularity for top 25"> <caption><h2>Popularity in 2012</h2></caption> <tr align="center" valign="bottom"> <th scope="col" width="12%" bgcolor="#efefef">Rank</th> <th scope="col" width="$colwidth" bgcolor="#99ccff">Male name</th> <th scope="col" bgcolor="pink" width="41%">Female name</th></tr> <tr align="right"> <td>1</td> <td>Jacob</td> <td>Sophia</td> </tr> <tr align="right"> <td>2</td> <td>Mason</td> <td>Emma</td> </tr> <tr align="right"> <td>3</td> <td>Ethan</td> <td>Isabella</td> </tr> <tr align="right"> <td>4</td> <td>Noah</td> <td>Olivia</td> </tr> <tr align="right"> <td>5</td> <td>William</td> <td>Ava</td> </tr> <tr align="right"> <td>6</td> <td>Liam</td> <td>Emily</td> </tr> <tr align="right"> <td>7</td> <td>Michael</td> <td>Abigail</td> </tr> <tr align="right"> <td>8</td> <td>Jayden</td> <td>Mia</td> </tr> <tr align="right"> <td>9</td> <td>Alexander</td> <td>Madison</td> </tr> <tr align="right"> <td>10</td> <td>Aiden</td> <td>Elizabeth</td> </tr> <tr align="right"> <td>11</td> <td>Daniel</td> <td>Chloe</td> </tr> <tr align="right"> <td>12</td> <td>Matthew</td> <td>Ella</td> </tr> <tr align="right"> <td>13</td> <td>Elijah</td> <td>Avery</td> </tr> <tr align="right"> <td>14</td> <td>James</td> <td>Addison</td> </tr> <tr align="right"> <td>15</td> <td>Anthony</td> <td>Aubrey</td> </tr> <tr align="right"> <td>16</td> <td>Benjamin</td> <td>Lily</td> </tr> <tr align="right"> <td>17</td> <td>Joshua</td> <td>Natalie</td> </tr> <tr align="right"> <td>18</td> <td>Andrew</td> <td>Sofia</td> </tr> <tr align="right"> <td>19</td> <td>Joseph</td> <td>Charlotte</td> </tr> <tr align="right"> <td>20</td> <td>David</td> <td>Zoey</td> </tr> <tr align="right"> <td>21</td> <td>Jackson</td> <td>Grace</td> </tr> <tr align="right"> <td>22</td> <td>Logan</td> <td>Hannah</td> </tr> <tr align="right"> <td>23</td> <td>Christopher</td> <td>Amelia</td> </tr> <tr align="right"> <td>24</td> <td>Gabriel</td> <td>Harper</td> </tr> <tr align="right"> <td>25</td> <td>Samuel</td> <td>Lillian</td> </tr> <tr><td colspan="3"><small>Note: Rank 1 is the most popular, rank 2 is the next most popular, and so forth. </table></p> </td></tr></table> <table class="printhide" width="100%" border="0" cellpadding="1" cellspacing="0"> <tr bgcolor="#333366"><td height="1" colspan="2"></td></tr> <tr> <td width="26%" valign="middle">&nbsp;</td> <td valign="top" class="seventypercent"> <a href="http://www.ssa.gov/privacy.html">Privacy Policy</a>&nbsp; | <a href="http://www.ssa.gov/websitepolicies.htm">Website Policies &amp; Other Important Information</a>&nbsp; | <a href="http://www.ssa.gov/sitemap.htm">Site Map</a></td> </tr> </table> </body></html>'; my $regex = qr/<.*?>(\d{1,2})<.*?>\s*<.*?>(.*?)<.*?>\s*<.*?>(.*?)<.*?>/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