114 lines
6.7 KiB
HTML
114 lines
6.7 KiB
HTML
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<!-- This manual documents Guile version 3.0.10.
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Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
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Copyright (C) 2021 Maxime Devos
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Copyright (C) 2024 Tomas Volf
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Permission is granted to copy, distribute and/or modify this document
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any later version published by the Free Software Foundation; with no
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Documentation License." -->
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<title>List Searching (Guile Reference Manual)</title>
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<meta name="description" content="List Searching (Guile Reference Manual)">
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<link href="index.html" rel="start" title="Top">
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<link href="Concept-Index.html" rel="index" title="Concept Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Lists.html" rel="up" title="Lists">
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<link href="List-Mapping.html" rel="next" title="List Mapping">
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<link href="List-Modification.html" rel="prev" title="List Modification">
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<div class="subsubsection-level-extent" id="List-Searching">
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<div class="nav-panel">
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<p>
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Next: <a href="List-Mapping.html" accesskey="n" rel="next">List Mapping</a>, Previous: <a href="List-Modification.html" accesskey="p" rel="prev">List Modification</a>, Up: <a href="Lists.html" accesskey="u" rel="up">Lists</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<h4 class="subsubsection" id="List-Searching-1"><span>6.6.9.7 List Searching<a class="copiable-link" href="#List-Searching-1"> ¶</a></span></h4>
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<p>The following procedures search lists for particular elements. They use
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different comparison predicates for comparing list elements with the
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object to be searched. When they fail, they return <code class="code">#f</code>, otherwise
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they return the sublist whose car is equal to the search object, where
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equality depends on the equality predicate used.
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</p>
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<a class="index-entry-id" id="index-memq-2"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-memq"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">memq</strong> <var class="def-var-arguments">x lst</var><a class="copiable-link" href="#index-memq"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fmemq"><span class="category-def">C Function: </span><span><strong class="def-name">scm_memq</strong> <var class="def-var-arguments">(x, lst)</var><a class="copiable-link" href="#index-scm_005fmemq"> ¶</a></span></dt>
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<dd><p>Return the first sublist of <var class="var">lst</var> whose car is <code class="code">eq?</code>
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to <var class="var">x</var> where the sublists of <var class="var">lst</var> are the non-empty
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lists returned by <code class="code">(list-tail <var class="var">lst</var> <var class="var">k</var>)</code> for
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<var class="var">k</var> less than the length of <var class="var">lst</var>. If <var class="var">x</var> does not
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occur in <var class="var">lst</var>, then <code class="code">#f</code> (not the empty list) is
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returned.
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</p></dd></dl>
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<a class="index-entry-id" id="index-memv-2"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-memv"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">memv</strong> <var class="def-var-arguments">x lst</var><a class="copiable-link" href="#index-memv"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fmemv"><span class="category-def">C Function: </span><span><strong class="def-name">scm_memv</strong> <var class="def-var-arguments">(x, lst)</var><a class="copiable-link" href="#index-scm_005fmemv"> ¶</a></span></dt>
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<dd><p>Return the first sublist of <var class="var">lst</var> whose car is <code class="code">eqv?</code>
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to <var class="var">x</var> where the sublists of <var class="var">lst</var> are the non-empty
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lists returned by <code class="code">(list-tail <var class="var">lst</var> <var class="var">k</var>)</code> for
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<var class="var">k</var> less than the length of <var class="var">lst</var>. If <var class="var">x</var> does not
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occur in <var class="var">lst</var>, then <code class="code">#f</code> (not the empty list) is
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returned.
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</p></dd></dl>
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<a class="index-entry-id" id="index-member-3"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-member"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">member</strong> <var class="def-var-arguments">x lst</var><a class="copiable-link" href="#index-member"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fmember"><span class="category-def">C Function: </span><span><strong class="def-name">scm_member</strong> <var class="def-var-arguments">(x, lst)</var><a class="copiable-link" href="#index-scm_005fmember"> ¶</a></span></dt>
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<dd><p>Return the first sublist of <var class="var">lst</var> whose car is
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<code class="code">equal?</code> to <var class="var">x</var> where the sublists of <var class="var">lst</var> are
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the non-empty lists returned by <code class="code">(list-tail <var class="var">lst</var>
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<var class="var">k</var>)</code> for <var class="var">k</var> less than the length of <var class="var">lst</var>. If
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<var class="var">x</var> does not occur in <var class="var">lst</var>, then <code class="code">#f</code> (not the
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empty list) is returned.
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</p>
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<p>See also SRFI-1 which has an extended <code class="code">member</code> function
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(<a class="ref" href="SRFI_002d1-Searching.html">Searching</a>).
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</p></dd></dl>
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</div>
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<hr>
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<div class="nav-panel">
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<p>
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Next: <a href="List-Mapping.html">List Mapping</a>, Previous: <a href="List-Modification.html">List Modification</a>, Up: <a href="Lists.html">Lists</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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