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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>9.2 Matching Regexp Patterns</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" 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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,"tocview_1");">▼</a></td><td>9 </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 </td><td><a href="regexp-intro.html" class="tocviewlink" data-pltdoc="x">Writing Regexp Patterns</a></td></tr><tr><td align="right">9.2 </td><td><a href="regexp-match.html" class="tocviewselflink" data-pltdoc="x">Matching Regexp Patterns</a></td></tr><tr><td align="right">9.3 </td><td><a href="regexp-assert.html" class="tocviewlink" data-pltdoc="x">Basic Assertions</a></td></tr><tr><td align="right">9.4 </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 </td><td><a href="regexp-quant.html" class="tocviewlink" data-pltdoc="x">Quantifiers</a></td></tr><tr><td align="right">9.6 </td><td><a href="regexp-clusters.html" class="tocviewlink" data-pltdoc="x">Clusters</a></td></tr><tr><td align="right">9.7 </td><td><a href="regexp-alternation.html" class="tocviewlink" data-pltdoc="x">Alternation</a></td></tr><tr><td align="right">9.8 </td><td><a href="Backtracking.html" class="tocviewlink" data-pltdoc="x">Backtracking</a></td></tr><tr><td align="right">9.9 </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 </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" 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://download.racket-lang.org/releases/8.6/doc/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-intro.html" title="backward to "9.1 Writing Regexp Patterns"" data-pltdoc="x">← prev</a> <a href="regexp.html" title="up to "9 Regular Expressions"" data-pltdoc="x">up</a> <a href="regexp-assert.html" title="forward to "9.3 Basic Assertions"" data-pltdoc="x">next →</a></span> </div><h4 x-source-module="(lib "scribblings/guide/guide.scrbl")" x-source-pkg="racket-doc" x-part-tag=""regexp-match"">9.2<tt> </tt><a name="(part._regexp-match)"></a>Matching Regexp Patterns</h4><p>The <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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span> function takes a <a href="regexp.html#%28tech._regexp%29" class="techoutside" data-pltdoc="x"><span class="techinside">regexp</span></a>
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pattern and a <a href="regexp.html#%28tech._text._string%29" class="techoutside" data-pltdoc="x"><span class="techinside">text string</span></a>, and it returns a match if the regexp
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matches (some part of) the <a href="regexp.html#%28tech._text._string%29" class="techoutside" data-pltdoc="x"><span class="techinside">text string</span></a>, or <span class="RktVal">#f</span> if the regexp
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did not match the string. A successful match produces a list of
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<a name="(tech._index._pair)"></a><span style="font-style: italic">index pairs</span>.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace"> </span><span class="RktVal">#rx"brain"</span><span class="hspace"> </span><span class="RktVal">"bird"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span><span class="hspace"> </span><span class="RktVal">#rx"needle"</span><span class="hspace"> </span><span class="RktVal">"hay needle stack"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'((4 . 10))</span></p></td></tr></table></blockquote></div></p><p>In the second example, the integers <span class="RktVal">4</span> and <span class="RktVal">10</span>
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identify the substring that was matched. The <span class="RktVal">4</span> is the
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starting (inclusive) index, and <span class="RktVal">10</span> the ending (exclusive)
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index of the matching substring:</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=strings.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._substring%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">substring</a></span><span class="hspace"> </span><span class="RktVal">"hay needle stack"</span><span class="hspace"> </span><span class="RktVal">4</span><span class="hspace"> </span><span class="RktVal">10</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">"needle"</span></p></td></tr></table></blockquote><p>In this first example, <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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span>’s return list
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contains only one index pair, and that pair represents the entire
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substring matched by the regexp. When we discuss <a href="regexp-clusters.html#%28tech._subpattern%29" class="techoutside" data-pltdoc="x"><span class="techinside">subpatterns</span></a>
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later, we will see how a single match operation can yield a list of
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<a href="regexp-clusters.html#%28tech._submatch%29" class="techoutside" data-pltdoc="x"><span class="techinside">submatch</span></a>es.</p><p>The <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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span> function takes optional third and
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fourth arguments that specify the indices of the <a href="regexp.html#%28tech._text._string%29" class="techoutside" data-pltdoc="x"><span class="techinside">text string</span></a> within
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which the matching should take place.</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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktVal">#rx"needle"</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktVal">"his needle stack -- my needle stack -- her needle stack"</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktVal">20</span><span class="hspace"> </span><span class="RktVal">39</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><p><span class="RktRes">'((23 . 29))</span></p></td></tr></table></blockquote><p>Note that the returned indices are still reckoned relative to the full
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<a href="regexp.html#%28tech._text._string%29" class="techoutside" data-pltdoc="x"><span class="techinside">text string</span></a>.</p><p>The <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> function is like
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<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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span>, but instead of returning index pairs,
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it returns the matching substrings:</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"brain"</span><span class="hspace"> </span><span class="RktVal">"bird"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</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">#rx"needle"</span><span class="hspace"> </span><span class="RktVal">"hay needle stack"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("needle")</span></p></td></tr></table></blockquote><p>When <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> is used with byte-string regexp, the result
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is a matching byte substring:</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#"needle"</span><span class="hspace"> </span><span class="RktVal">#"hay needle stack"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'(#"needle")</span></p></td></tr></table></blockquote><blockquote class="refpara"><blockquote class="refcolumn"><blockquote class="refcontent"><p>A byte-string regexp can be applied to a string, and a
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string regexp can be applied to a byte string. In both
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cases, the result is a byte string. Internally, all
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regexp matching is in terms of bytes, and a string regexp
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is expanded to a regexp that matches UTF-8 encodings of
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characters. For maximum efficiency, use byte-string
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matching instead of string, since matching bytes directly
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avoids UTF-8 encodings.</p></blockquote></blockquote></blockquote><p>If you have data that is in a port, there’s no need to first read it
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into a string. Functions like <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> can match on the
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port directly:</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=define.html%23%2528form._%2528%2528quote._%7E23%7E25kernel%2529._define-values%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">define-values</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">i</span><span class="hspace"> </span><span class="RktSym">o</span><span class="RktPn">)</span><span class="hspace"> </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=pipeports.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._make-pipe%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">make-pipe</a></span><span class="RktPn">)</span><span class="RktPn">)</span></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=Writing.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._write%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">write</a></span><span class="hspace"> </span><span class="RktVal">"hay needle stack"</span><span class="hspace"> </span><span class="RktSym">o</span><span class="RktPn">)</span></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=port-ops.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._close-output-port%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">close-output-port</a></span><span class="hspace"> </span><span class="RktSym">o</span><span class="RktPn">)</span></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">#rx#"needle"</span><span class="hspace"> </span><span class="RktSym">i</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'(#"needle")</span></p></td></tr></table></blockquote><p>The <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%7E3f%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match?</a></span> function is like
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<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-positions%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match-positions</a></span>, but simply returns a boolean
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indicating whether the match succeeded:</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%7E3f%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match?</a></span><span class="hspace"> </span><span class="RktVal">#rx"brain"</span><span class="hspace"> </span><span class="RktVal">"bird"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</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%7E3f%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-match?</a></span><span class="hspace"> </span><span class="RktVal">#rx"needle"</span><span class="hspace"> </span><span class="RktVal">"hay needle stack"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#t</span></p></td></tr></table></blockquote><p>The <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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span> function takes two arguments, a
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<a href="regexp.html#%28tech._regexp%29" class="techoutside" data-pltdoc="x"><span class="techinside">regexp</span></a> pattern and a text string, and it returns a list of
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substrings of the text string; the pattern identifies the delimiter
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separating the substrings.</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span><span class="hspace"> </span><span class="RktVal">#rx":"</span><span class="hspace"> </span><span class="RktVal">"/bin:/usr/bin:/usr/bin/X11:/usr/local/bin"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("/bin" "/usr/bin" "/usr/bin/X11" "/usr/local/bin")</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span><span class="hspace"> </span><span class="RktVal">#rx" "</span><span class="hspace"> </span><span class="RktVal">"pea soup"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("pea" "soup")</span></p></td></tr></table></blockquote><p>If the first argument matches empty strings, then the list of all the
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single-character substrings is returned.</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span><span class="hspace"> </span><span class="RktVal">#rx""</span><span class="hspace"> </span><span class="RktVal">"smithereens"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("" "s" "m" "i" "t" "h" "e" "r" "e" "e" "n" "s" "")</span></p></td></tr></table></blockquote><p>Thus, to identify one-or-more spaces as the delimiter, take care to
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use the regexp <span class="RktVal">#rx" +"</span>, not <span class="RktVal">#rx" *"</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span><span class="hspace"> </span><span class="RktVal">#rx" +"</span><span class="hspace"> </span><span class="RktVal">"split pea</span><span class="hspace"> </span><span class="RktVal">soup"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("split" "pea" "soup")</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-split%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-split</a></span><span class="hspace"> </span><span class="RktVal">#rx" *"</span><span class="hspace"> </span><span class="RktVal">"split pea</span><span class="hspace"> </span><span class="RktVal">soup"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'("" "s" "p" "l" "i" "t" "" "p" "e" "a" "" "s" "o" "u" "p" "")</span></p></td></tr></table></blockquote><p>The <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-replace%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace</a></span> function replaces the matched portion of
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the text string by another string. The first argument is the pattern,
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the second the text string, and the third is either the string to be
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inserted or a procedure to convert matches to the insert string.</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-replace%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace</a></span><span class="hspace"> </span><span class="RktVal">#rx"te"</span><span class="hspace"> </span><span class="RktVal">"liberte"</span><span class="hspace"> </span><span class="RktVal">"ty"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">"liberty"</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-replace%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace</a></span><span class="hspace"> </span><span class="RktVal">#rx"."</span><span class="hspace"> </span><span class="RktVal">"racket"</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=strings.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._string-upcase%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">string-upcase</a></span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">"Racket"</span></p></td></tr></table></blockquote><p>If the pattern doesn’t occur in the text string, the returned string
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is identical to the text string.</p><p>The <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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-replace%252A%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace*</a></span> function replaces <span class="emph">all</span> matches in
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the text string by the insert string:</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-replace%252A%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace*</a></span><span class="hspace"> </span><span class="RktVal">#rx"te"</span><span class="hspace"> </span><span class="RktVal">"liberte egalite fraternite"</span><span class="hspace"> </span><span class="RktVal">"ty"</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">"liberty egality fratyrnity"</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%2528lib._racket%252Fprivate%252Fbase..rkt%2529._regexp-replace%252A%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">regexp-replace*</a></span><span class="hspace"> </span><span class="RktVal">#rx"[ds]"</span><span class="hspace"> </span><span class="RktVal">"drracket"</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=reference&rel=strings.html%23%2528def._%2528%2528quote._%7E23%7E25kernel%2529._string-upcase%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">string-upcase</a></span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">"Drracket"</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://download.racket-lang.org/releases/8.6/doc/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-intro.html" title="backward to "9.1 Writing Regexp Patterns"" data-pltdoc="x">← prev</a> <a href="regexp.html" title="up to "9 Regular Expressions"" data-pltdoc="x">up</a> <a href="regexp-assert.html" title="forward to "9.3 Basic Assertions"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html> |