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<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><meta name="viewport" content="width=device-width, initial-scale=0.8"/><title>9.4 Characters and Character Classes</title><link rel="stylesheet" type="text/css" href="../scribble.css" title="default"/><link rel="stylesheet" type="text/css" href="../racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-style.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../doc-site.css" title="default"/><script type="text/javascript" src="../scribble-common.js"></script><script type="text/javascript" src="../manual-racket.js"></script><script type="text/javascript" src="../manual-racket.js"></script><script type="text/javascript" src="../doc-site.js"></script><script type="text/javascript" src="../local-redirect/local-redirect.js"></script><script type="text/javascript" src="../local-redirect/local-user-redirect.js"></script><!--[if IE 6]><style type="text/css">.SIEHidden { overflow: hidden; }</style><![endif]--></head><body id="doc-racket-lang-org"><div class="tocset"><div class="tocview"><div class="tocviewlist tocviewlisttopspace"><div class="tocviewtitle"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,"tocview_0");">►</a></td><td></td><td><a href="index.html" class="tocviewlink" data-pltdoc="x">The Racket Guide</a></td></tr></table></div><div class="tocviewsublisttop" style="display: none;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1 </td><td><a href="intro.html" class="tocviewlink" data-pltdoc="x">Welcome to Racket</a></td></tr><tr><td align="right">2 </td><td><a href="to-scheme.html" class="tocviewlink" data-pltdoc="x">Racket Essentials</a></td></tr><tr><td align="right">3 </td><td><a href="datatypes.html" class="tocviewlink" data-pltdoc="x">Built-<wbr></wbr>In Datatypes</a></td></tr><tr><td align="right">4 </td><td><a href="scheme-forms.html" class="tocviewlink" data-pltdoc="x">Expressions and Definitions</a></td></tr><tr><td align="right">5 </td><td><a href="define-struct.html" class="tocviewlink" data-pltdoc="x">Programmer-<wbr></wbr>Defined Datatypes</a></td></tr><tr><td align="right">6 </td><td><a href="modules.html" class="tocviewlink" data-pltdoc="x">Modules</a></td></tr><tr><td align="right">7 </td><td><a href="contracts.html" class="tocviewlink" data-pltdoc="x">Contracts</a></td></tr><tr><td align="right">8 </td><td><a href="i_o.html" class="tocviewlink" data-pltdoc="x">Input and Output</a></td></tr><tr><td align="right">9 </td><td><a href="regexp.html" class="tocviewselflink" data-pltdoc="x">Regular Expressions</a></td></tr><tr><td align="right">10 </td><td><a href="control.html" class="tocviewlink" data-pltdoc="x">Exceptions and Control</a></td></tr><tr><td align="right">11 </td><td><a href="for.html" class="tocviewlink" data-pltdoc="x">Iterations and Comprehensions</a></td></tr><tr><td align="right">12 </td><td><a href="match.html" class="tocviewlink" data-pltdoc="x">Pattern Matching</a></td></tr><tr><td align="right">13 </td><td><a href="classes.html" class="tocviewlink" data-pltdoc="x">Classes and Objects</a></td></tr><tr><td align="right">14 </td><td><a href="units.html" class="tocviewlink" data-pltdoc="x">Units</a></td></tr><tr><td align="right">15 </td><td><a href="reflection.html" class="tocviewlink" data-pltdoc="x">Reflection and Dynamic Evaluation</a></td></tr><tr><td align="right">16 </td><td><a href="macros.html" class="tocviewlink" data-pltdoc="x">Macros</a></td></tr><tr><td align="right">17 </td><td><a href="languages.html" class="tocviewlink" data-pltdoc="x">Creating Languages</a></td></tr><tr><td align="right">18 </td><td><a href="concurrency.html"
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text string. Sometimes it is necessary or convenient to use a regexp
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<a href="regexp-intro.html#%28tech._metasequence%29" class="techoutside" data-pltdoc="x"><span class="techinside">metasequence</span></a> to refer to a single character. For example, the
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metasequence <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\.</span><span class="hspace"></span></span> matches the period character.</p><p>The <a href="regexp-intro.html#%28tech._metacharacter%29" class="techoutside" data-pltdoc="x"><span class="techinside">metacharacter</span></a> <span class="RktInBG"><span class="hspace"></span><span class="RktIn">.</span><span class="hspace"></span></span> matches <span class="emph">any</span> character
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(other than newline in <a href="regexp-clusters.html#%28tech._multi._line._mode%29" class="techoutside" data-pltdoc="x"><span class="techinside">multi-line mode</span></a>; see
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<a href="regexp-clusters.html#%28part._regexp-cloister%29" data-pltdoc="x">Cloisters</a>):</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#rx"p.t"</span><span class="hspace"> </span><span class="RktVal">"pet"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("pet")</span></p></td></tr></table></blockquote><p>The above pattern also matches <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pat</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pit</span><span class="hspace"></span></span>,
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">pot</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">put</span><span class="hspace"></span></span>, and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">p8t</span><span class="hspace"></span></span>, but not
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">peat</span><span class="hspace"></span></span> or <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pfffft</span><span class="hspace"></span></span>.</p><p>A <a name="(tech._character._clas)"></a><span style="font-style: italic">character class</span> matches any one character from a set of
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characters. A typical format for this is the <a name="(tech._bracketed._character._clas)"></a><span style="font-style: italic">bracketed
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character class</span> <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[</span><span class="hspace"></span></span>...<span class="RktInBG"><span class="hspace"></span><span class="RktIn">]</span><span class="hspace"></span></span>, which matches any one
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character from the non-empty sequence of characters enclosed within
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the brackets. Thus, <span class="RktVal">#rx"p[aeiou]t"</span> matches <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pat</span><span class="hspace"></span></span>,
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">pet</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pit</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">pot</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">put</span><span class="hspace"></span></span>, and
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nothing else.</p><p>Inside the brackets, a <span class="RktInBG"><span class="hspace"></span><span class="RktIn">-</span><span class="hspace"></span></span> between two characters specifies
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the Unicode range between the characters. For example,
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<span class="RktVal">#rx"ta[b-dgn-p]"</span> matches <span class="RktInBG"><span class="hspace"></span><span class="RktIn">tab</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">tac</span><span class="hspace"></span></span>,
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">tad</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">tag</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">tan</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">tao</span><span class="hspace"></span></span>, and
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">tap</span><span class="hspace"></span></span>.</p><p>An initial <span class="RktInBG"><span class="hspace"></span><span class="RktIn">^</span><span class="hspace"></span></span> after the left bracket inverts the set
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specified by the rest of the contents; i.e., it specifies the set of
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characters <span class="emph">other than</span> those identified in the brackets. For
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example, <span class="RktVal">#rx"do[^g]"</span> matches all three-character sequences
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starting with <span class="RktInBG"><span class="hspace"></span><span class="RktIn">do</span><span class="hspace"></span></span> except <span class="RktInBG"><span class="hspace"></span><span class="RktIn">dog</span><span class="hspace"></span></span>.</p><p>Note that the <a href="regexp-intro.html#%28tech._metacharacter%29" class="techoutside" data-pltdoc="x"><span class="techinside">metacharacter</span></a> <span class="RktInBG"><span class="hspace"></span><span class="RktIn">^</span><span class="hspace"></span></span> inside brackets means
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something quite different from what it means outside. Most other
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<a href="regexp-intro.html#%28tech._metacharacter%29" class="techoutside" data-pltdoc="x"><span class="techinside">metacharacters</span></a> (<span class="RktInBG"><span class="hspace"></span><span class="RktIn">.</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">*</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">+</span><span class="hspace"></span></span>,
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">?</span><span class="hspace"></span></span>, etc.) cease to be <a href="regexp-intro.html#%28tech._metacharacter%29" class="techoutside" data-pltdoc="x"><span class="techinside">metacharacters</span></a> when inside
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brackets, although you may still escape them for peace of mind. A
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">-</span><span class="hspace"></span></span> is a <a href="regexp-intro.html#%28tech._metacharacter%29" class="techoutside" data-pltdoc="x"><span class="techinside">metacharacter</span></a> only when it’s inside brackets,
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and when it is neither the first nor the last character between the
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brackets.</p><p>Bracketed character classes cannot contain other bracketed character
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classes (although they contain certain other types of character
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classes; see below). Thus, a <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[</span><span class="hspace"></span></span> inside a bracketed character
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class doesn’t have to be a metacharacter; it can stand for itself.
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For example, <span class="RktVal">#rx"[a[b]"</span> matches <span class="RktInBG"><span class="hspace"></span><span class="RktIn">a</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[</span><span class="hspace"></span></span>, and
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">b</span><span class="hspace"></span></span>.</p><p>Furthermore, since empty bracketed character classes are disallowed, a
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">]</span><span class="hspace"></span></span> immediately occurring after the opening left bracket also
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doesn’t need to be a metacharacter. For example, <span class="RktVal">#rx"[]ab]"</span>
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matches <span class="RktInBG"><span class="hspace"></span><span class="RktIn">]</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">a</span><span class="hspace"></span></span>, and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">b</span><span class="hspace"></span></span>.</p><h5 x-source-module="(lib "scribblings/guide/guide.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Some_Frequently_Used_Character_Classes"">9.4.1<tt> </tt><a name="(part._.Some_.Frequently_.Used_.Character_.Classes)"></a>Some Frequently Used Character Classes</h5><p>In <span class="RktInBG"><span class="hspace"></span><span class="RktIn">#px</span><span class="hspace"></span></span> syntax, some standard character classes can be
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conveniently represented as metasequences instead of as explicit
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bracketed expressions: <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\d</span><span class="hspace"></span></span> matches a digit
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(the same as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[0-9]</span><span class="hspace"></span></span>); <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\s</span><span class="hspace"></span></span> matches an ASCII whitespace character; and
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">\w</span><span class="hspace"></span></span> matches a character that could be part of a
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“word”.</p><blockquote class="refpara"><blockquote class="refcolumn"><blockquote class="refcontent"><p>Following regexp custom, we identify “word” characters
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as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[A-Za-z0-9_]</span><span class="hspace"></span></span>, although these are too restrictive for what
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a Racketeer might consider a “word.”</p></blockquote></blockquote></blockquote><p>The upper-case versions of these metasequences stand for the
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inversions of the corresponding character classes: <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\D</span><span class="hspace"></span></span>
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matches a non-digit, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\S</span><span class="hspace"></span></span> a non-whitespace character, and
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">\W</span><span class="hspace"></span></span> a non-“word” character.</p><p>Remember to include a double backslash when putting these
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metasequences in a Racket string:</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"\\d\\d"</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktVal">"0 dear, 1 have 2 read catch 22 before 9"</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><p><span class="RktRes">'("22")</span></p></td></tr></table></blockquote><p>These character classes can be used inside a bracketed expression. For
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example, <span class="RktVal">#px"[a-z\\d]"</span> matches a lower-case letter or a
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digit.</p><h5 x-source-module="(lib "scribblings/guide/guide.scrbl")" x-source-pkg="racket-doc" x-part-tag=""POSIX_character_classes"">9.4.2<tt> </tt><a name="(part._.P.O.S.I.X_character_classes)"></a>POSIX character classes</h5><p>A <a name="(tech._posix._character._clas)"></a><span style="font-style: italic">POSIX character class</span> is a special <a href="regexp-intro.html#%28tech._metasequence%29" class="techoutside" data-pltdoc="x"><span class="techinside">metasequence</span></a> of
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the form <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:</span><span class="hspace"></span></span>...<span class="RktInBG"><span class="hspace"></span><span class="RktIn">:]</span><span class="hspace"></span></span> that can be used only inside a
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bracketed expression in <span class="RktInBG"><span class="hspace"></span><span class="RktIn">#px</span><span class="hspace"></span></span> syntax. The POSIX classes
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supported are</p><ul class="compact"><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:alnum:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII letters and digits</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:alpha:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII letters</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:ascii:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII characters</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:blank:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII widthful whitespace: space and tab</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:cntrl:]</span><span class="hspace"></span></span> —<wbr></wbr> “control” characters: ASCII 0 to 31</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:digit:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII digits, same as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\d</span><span class="hspace"></span></span></p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:graph:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII characters that use ink</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:lower:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII lower-case letters</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:print:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII ink-users plus widthful whitespace</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:space:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII whitespace, same as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\s</span><span class="hspace"></span></span></p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:upper:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII upper-case letters</p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:word:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII letters and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">_</span><span class="hspace"></span></span>, same as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">\w</span><span class="hspace"></span></span></p></li><li class="compactItem"><p><span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:xdigit:]</span><span class="hspace"></span></span> —<wbr></wbr> ASCII hex digits</p></li></ul><p>For example, the <span class="RktVal">#px"[[:alpha:]_]"</span> matches a letter or
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underscore.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"[[:alpha:]_]"</span><span class="hspace"> </span><span class="RktVal">"--x--"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("x")</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"[[:alpha:]_]"</span><span class="hspace"> </span><span class="RktVal">"--_--"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("_")</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"[[:alpha:]_]"</span><span class="hspace"> </span><span class="RktVal">"--:--"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr></table></blockquote><p>The POSIX class notation is valid <span class="emph">only</span> inside a bracketed
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expression. For instance, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">[:alpha:]</span><span class="hspace"></span></span>, when not inside a
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bracketed expression, will not be read as the letter class. Rather,
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it is (from previous principles) the character class containing the
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characters <span class="RktInBG"><span class="hspace"></span><span class="RktIn">:</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">a</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">l</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">p</span><span class="hspace"></span></span>,
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">h</span><span class="hspace"></span></span>.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"[:alpha:]"</span><span class="hspace"> </span><span class="RktVal">"--a--"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("a")</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace"> </span><span class="RktVal">#px"[:alpha:]"</span><span class="hspace"> </span><span class="RktVal">"--x--"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr></table></blockquote><div class="navsetbottom"><span class="navleft"><form class="searchform"><input class="searchbox" id="searchbox" type="text" tabindex="1" placeholder="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, "8.6", "../");"/></form> <a href="https://docs.racket-lang.org/index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot("8.6");">top</a><span class="tocsettoggle"> <a href="javascript:void(0);" title="show/hide table of contents" onclick="TocsetToggle();">contents</a></span></span><span class="navright"> <a href="regexp-assert.html" title="backward to "9.3 Basic Assertions"" data-pltdoc="x">← prev</a> <a href="regexp.html" title="up to "9 Regular Expressions"" data-pltdoc="x">up</a> <a href="regexp-quant.html" title="forward to "9.5 Quantifiers"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
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