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<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><title>9.5&nbsp;Quantifiers</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,&quot;tocview_0&quot;);">&#9658;</a></td><td></td><td><a href="index.html" class="tocviewlink" data-pltdoc="x"><span style="font-weight: bold">The Racket Guide</span></a></td></tr></table></div><div class="tocviewsublisttop" style="display: none;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1&nbsp;</td><td><a href="intro.html" class="tocviewlink" data-pltdoc="x">Welcome to Racket</a></td></tr><tr><td align="right">2&nbsp;</td><td><a href="to-scheme.html" class="tocviewlink" data-pltdoc="x">Racket Essentials</a></td></tr><tr><td align="right">3&nbsp;</td><td><a href="datatypes.html" class="tocviewlink" data-pltdoc="x">Built-<wbr></wbr>In Datatypes</a></td></tr><tr><td align="right">4&nbsp;</td><td><a href="scheme-forms.html" class="tocviewlink" data-pltdoc="x">Expressions and Definitions</a></td></tr><tr><td align="right">5&nbsp;</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&nbsp;</td><td><a href="modules.html" class="tocviewlink" data-pltdoc="x">Modules</a></td></tr><tr><td align="right">7&nbsp;</td><td><a href="contracts.html" class="tocviewlink" data-pltdoc="x">Contracts</a></td></tr><tr><td align="right">8&nbsp;</td><td><a href="i_o.html" class="tocviewlink" data-pltdoc="x">Input and Output</a></td></tr><tr><td align="right">9&nbsp;</td><td><a href="regexp.html" class="tocviewselflink" data-pltdoc="x">Regular Expressions</a></td></tr><tr><td align="right">10&nbsp;</td><td><a href="control.html" class="tocviewlink" data-pltdoc="x">Exceptions and Control</a></td></tr><tr><td align="right">11&nbsp;</td><td><a href="for.html" class="tocviewlink" data-pltdoc="x">Iterations and Comprehensions</a></td></tr><tr><td align="right">12&nbsp;</td><td><a href="match.html" class="tocviewlink" data-pltdoc="x">Pattern Matching</a></td></tr><tr><td align="right">13&nbsp;</td><td><a href="classes.html" class="tocviewlink" data-pltdoc="x">Classes and Objects</a></td></tr><tr><td align="right">14&nbsp;</td><td><a href="units.html" class="tocviewlink" data-pltdoc="x">Units (Components)</a></td></tr><tr><td align="right">15&nbsp;</td><td><a href="reflection.html" class="tocviewlink" data-pltdoc="x">Reflection and Dynamic Evaluation</a></td></tr><tr><td align="right">16&nbsp;</td><td><a href="macros.html" class="tocviewlink" data-pltdoc="x">Macros</a></td></tr><tr><td align="right">17&nbsp;</td><td><a href="languages.html" class="tocviewlink" 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Tools and Your Editor of Choice</a></td></tr><tr><td align="right"></td><td><a href="doc-bibliography.html" class="tocviewlink" data-pltdoc="x">Bibliography</a></td></tr><tr><td align="right"></td><td><a href="doc-index.html" class="tocviewlink" data-pltdoc="x">Index</a></td></tr></table></div></div><div class="tocviewlist"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,&quot;tocview_1&quot;);">&#9660;</a></td><td>9&nbsp;</td><td><a href="regexp.html" class="tocviewlink" data-pltdoc="x">Regular Expressions</a></td></tr></table><div class="tocviewsublistbottom" style="display: block;" id="tocview_1"><table cellspacing="0" cellpadding="0"><tr><td align="right">9.1&nbsp;</td><td><a href="regexp-intro.html" class="tocviewlink" data-pltdoc="x">Writing Regexp Patterns</a></td></tr><tr><td align="right">9.2&nbsp;</td><td><a href="regexp-match.html" class="tocviewlink" data-pltdoc="x">Matching Regexp Patterns</a></td></tr><tr><td align="right">9.3&nbsp;</td><td><a href="regexp-assert.html" class="tocviewlink" data-pltdoc="x">Basic Assertions</a></td></tr><tr><td align="right">9.4&nbsp;</td><td><a href="regexp-chars.html" class="tocviewlink" data-pltdoc="x">Characters and Character Classes</a></td></tr><tr><td align="right">9.5&nbsp;</td><td><a href="" class="tocviewselflink" data-pltdoc="x">Quantifiers</a></td></tr><tr><td align="right">9.6&nbsp;</td><td><a href="regexp-clusters.html" class="tocviewlink" data-pltdoc="x">Clusters</a></td></tr><tr><td align="right">9.7&nbsp;</td><td><a href="regexp-alternation.html" class="tocviewlink" data-pltdoc="x">Alternation</a></td></tr><tr><td align="right">9.8&nbsp;</td><td><a href="Backtracking.html" class="tocviewlink" data-pltdoc="x">Backtracking</a></td></tr><tr><td align="right">9.9&nbsp;</td><td><a href="Looking_Ahead_and_Behind.html" class="tocviewlink" data-pltdoc="x">Looking Ahead and Behind</a></td></tr><tr><td align="right">9.10&nbsp;</td><td><a href="An_Extended_Example.html" class="tocviewlink" data-pltdoc="x">An Extended Example</a></td></tr></table></div></div></div></div><div class="maincolumn"><div class="main"><div class="navsettop"><span class="navleft"><form class="searchform"><input class="searchbox" style="color: #888;" type="text" value="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, &quot;6.1&quot;, &quot;../&quot;);" onfocus="this.style.color=&quot;black&quot;; this.style.textAlign=&quot;left&quot;; if (this.value == &quot;...search manuals...&quot;) this.value=&quot;&quot;;" onblur="if (this.value.match(/^ *$/)) { this.style.color=&quot;#888&quot;; this.style.textAlign=&quot;center&quot;; this.value=&quot;...search manuals...&quot;; }"/></form>&nbsp;&nbsp;<a href="../index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot(&quot;6.1&quot;);">top</a></span><span class="navright">&nbsp;&nbsp;<a href="regexp-chars.html" title="backward to &quot;9.4 Characters and Character Classes&quot;" data-pltdoc="x">&larr; prev</a>&nbsp;&nbsp;<a href="regexp.html" title="up to &quot;9 Regular Expressions&quot;" data-pltdoc="x">up</a>&nbsp;&nbsp;<a href="regexp-clusters.html" title="forward to &quot;9.6 Clusters&quot;" data-pltdoc="x">next &rarr;</a></span>&nbsp;</div><h4 x-source-module="(lib &quot;scribblings/guide/guide.scrbl&quot;)" x-part-tag="&quot;regexp-quant&quot;">9.5<tt>&nbsp;</tt><a name="(part._regexp-quant)"></a>Quantifiers</h4><p>The <a name="(tech._quantifier)"></a><span style="font-style: italic">quantifiers</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>, and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">?</span><span class="hspace"></span></span>
match respectively: zero or more, one or more, and zero or one
instances of the preceding subpattern.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]*r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cadaddadddr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((0 . 11))</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]*r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((0 . 2))</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]+r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cadaddadddr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((0 . 11))</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]+r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]?r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cadaddadddr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]?r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"cr"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((0 . 2))</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match-positions%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"c[ad]?r"</span><span class="hspace">&nbsp;</span><span class="RktVal">"car"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((0 . 3))</span></p></td></tr></table></blockquote><p>In <span class="RktInBG"><span class="hspace"></span><span class="RktIn">#px</span><span class="hspace"></span></span> syntax, you can use braces to specify much
finer-tuned quantification than is possible with <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>:</p><ul><li><p>The quantifier <span class="RktInBG"><span class="hspace"></span><span class="RktIn">{</span><span class="hspace"></span></span><span style="font-style: italic">m</span><span class="RktInBG"><span class="hspace"></span><span class="RktIn">}</span><span class="hspace"></span></span> matches
<span style="font-style: italic">exactly</span> <span style="font-style: italic">m</span> instances of the preceding
<a href="regexp-clusters.html#%28tech._subpattern%29" class="techoutside" data-pltdoc="x"><span class="techinside">subpattern</span></a>; <span style="font-style: italic">m</span> must be a nonnegative integer.</p></li><li><p>The quantifier
<span class="RktInBG"><span class="hspace"></span><span class="RktIn">{</span><span class="hspace"></span></span><span style="font-style: italic">m</span><span class="RktInBG"><span class="hspace"></span><span class="RktIn">,</span><span class="hspace"></span></span><span style="font-style: italic">n</span><span class="RktInBG"><span class="hspace"></span><span class="RktIn">}</span><span class="hspace"></span></span> matches
at least <span style="font-style: italic">m</span> and at most <span style="font-style: italic">n</span> instances.  <span class="RktInBG"><span class="hspace"></span><span class="RktIn">m</span><span class="hspace"></span></span>
and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">n</span><span class="hspace"></span></span> are nonnegative integers with <span style="font-style: italic">m</span> less or
equal to <span style="font-style: italic">n</span>.  You may omit either or both numbers, in
which case <span style="font-style: italic">m</span> defaults to <span style="font-style: italic"></span>0<span style="font-style: italic"></span> and <span style="font-style: italic">n</span> to
infinity.</p></li></ul><p>It is evident that <span class="RktInBG"><span class="hspace"></span><span class="RktIn">+</span><span class="hspace"></span></span> and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">?</span><span class="hspace"></span></span> are abbreviations for
<span class="RktInBG"><span class="hspace"></span><span class="RktIn">{1,}</span><span class="hspace"></span></span> and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">{0,1}</span><span class="hspace"></span></span> respectively, and <span class="RktInBG"><span class="hspace"></span><span class="RktIn">*</span><span class="hspace"></span></span>
abbreviates <span class="RktInBG"><span class="hspace"></span><span class="RktIn">{,}</span><span class="hspace"></span></span>, which is the same as <span class="RktInBG"><span class="hspace"></span><span class="RktIn">{0,}</span><span class="hspace"></span></span>.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#px"[aeiou]{3}"</span><span class="hspace">&nbsp;</span><span class="RktVal">"vacuous"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("uou")</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#px"[aeiou]{3}"</span><span class="hspace">&nbsp;</span><span class="RktVal">"evolve"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#px"[aeiou]{2,3}"</span><span class="hspace">&nbsp;</span><span class="RktVal">"evolve"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#px"[aeiou]{2,3}"</span><span class="hspace">&nbsp;</span><span class="RktVal">"zeugma"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("eu")</span></p></td></tr></table></blockquote><p>The quantifiers described so far are all <a name="(tech._greedy)"></a><span style="font-style: italic">greedy</span>: they match
the maximal number of instances that would still lead to an overall
match for the full pattern.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"&lt;.*&gt;"</span><span class="hspace">&nbsp;</span><span class="RktVal">"&lt;tag1&gt; &lt;tag2&gt; &lt;tag3&gt;"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("&lt;tag1&gt; &lt;tag2&gt; &lt;tag3&gt;")</span></p></td></tr></table></blockquote><p>To make these quantifiers <a name="(tech._non._greedy)"></a><span style="font-style: italic">non-greedy</span>, append a <span class="RktInBG"><span class="hspace"></span><span class="RktIn">?</span><span class="hspace"></span></span>
to them.  Non-greedy quantifiers match the minimal number of instances
needed to ensure an overall match.</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">&gt; </span><span class="RktPn">(</span><span class="RktSym"><a href="http://download.racket-lang.org/docs/6.1/html/local-redirect/index.html?doc=reference&amp;rel=regexp.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._regexp-match%2529%2529&amp;version=6.1" class="RktValLink Sq" data-pltdoc="x">regexp-match</a></span><span class="hspace">&nbsp;</span><span class="RktVal">#rx"&lt;.*?&gt;"</span><span class="hspace">&nbsp;</span><span class="RktVal">"&lt;tag1&gt; &lt;tag2&gt; &lt;tag3&gt;"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("&lt;tag1&gt;")</span></p></td></tr></table></blockquote><p>The non-greedy quantifiers are respectively: <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>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">{</span><span class="hspace"></span></span><span style="font-style: italic">m</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><span style="font-style: italic">m</span><span class="RktInBG"><span class="hspace"></span><span class="RktIn">,</span><span class="hspace"></span></span><span style="font-style: italic">n</span><span class="RktInBG"><span class="hspace"></span><span class="RktIn">}?</span><span class="hspace"></span></span>.  Note the two
uses of the metacharacter <span class="RktInBG"><span class="hspace"></span><span class="RktIn">?</span><span class="hspace"></span></span>.</p><div class="navsetbottom"><span class="navleft"><form class="searchform"><input class="searchbox" style="color: #888;" type="text" value="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, &quot;6.1&quot;, &quot;../&quot;);" onfocus="this.style.color=&quot;black&quot;; this.style.textAlign=&quot;left&quot;; if (this.value == &quot;...search manuals...&quot;) this.value=&quot;&quot;;" onblur="if (this.value.match(/^ *$/)) { this.style.color=&quot;#888&quot;; this.style.textAlign=&quot;center&quot;; this.value=&quot;...search manuals...&quot;; }"/></form>&nbsp;&nbsp;<a href="../index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot(&quot;6.1&quot;);">top</a></span><span class="navright">&nbsp;&nbsp;<a href="regexp-chars.html" title="backward to &quot;9.4 Characters and Character Classes&quot;" data-pltdoc="x">&larr; prev</a>&nbsp;&nbsp;<a href="regexp.html" title="up to &quot;9 Regular Expressions&quot;" data-pltdoc="x">up</a>&nbsp;&nbsp;<a href="regexp-clusters.html" title="forward to &quot;9.6 Clusters&quot;" data-pltdoc="x">next &rarr;</a></span>&nbsp;</div></div></div><div id="contextindicator">&nbsp;</div></body></html>