154 lines
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154 lines
11 KiB
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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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Inc.
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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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copy of the license is included in the section entitled "GNU Free
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Documentation License." -->
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<title>Miscellaneous String Operations (Guile Reference Manual)</title>
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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="Strings.html" rel="up" title="Strings">
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<link href="Representing-Strings-as-Bytes.html" rel="next" title="Representing Strings as Bytes">
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<body lang="en">
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<div class="subsubsection-level-extent" id="Miscellaneous-String-Operations">
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<div class="nav-panel">
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<p>
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Next: <a href="Representing-Strings-as-Bytes.html" accesskey="n" rel="next">Representing Strings as Bytes</a>, Previous: <a href="Mapping-Folding-and-Unfolding.html" accesskey="p" rel="prev">Mapping, Folding, and Unfolding</a>, Up: <a href="Strings.html" accesskey="u" rel="up">Strings</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="Miscellaneous-String-Operations-1"><span>6.6.5.12 Miscellaneous String Operations<a class="copiable-link" href="#Miscellaneous-String-Operations-1"> ¶</a></span></h4>
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<dl class="first-deffn">
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<dt class="deffn" id="index-xsubstring"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">xsubstring</strong> <var class="def-var-arguments">s from [to [start [end]]]</var><a class="copiable-link" href="#index-xsubstring"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fxsubstring"><span class="category-def">C Function: </span><span><strong class="def-name">scm_xsubstring</strong> <var class="def-var-arguments">(s, from, to, start, end)</var><a class="copiable-link" href="#index-scm_005fxsubstring"> ¶</a></span></dt>
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<dd><p>This is the <em class="emph">extended substring</em> procedure that implements
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replicated copying of a substring of some string.
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</p>
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<p><var class="var">s</var> is a string, <var class="var">start</var> and <var class="var">end</var> are optional
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arguments that demarcate a substring of <var class="var">s</var>, defaulting to
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0 and the length of <var class="var">s</var>. Replicate this substring up and
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down index space, in both the positive and negative directions.
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<code class="code">xsubstring</code> returns the substring of this string
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beginning at index <var class="var">from</var>, and ending at <var class="var">to</var>, which
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defaults to <var class="var">from</var> + (<var class="var">end</var> - <var class="var">start</var>).
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002dxcopy_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-xcopy!</strong> <var class="def-var-arguments">target tstart s sfrom [sto [start [end]]]</var><a class="copiable-link" href="#index-string_002dxcopy_0021"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fstring_005fxcopy_005fx"><span class="category-def">C Function: </span><span><strong class="def-name">scm_string_xcopy_x</strong> <var class="def-var-arguments">(target, tstart, s, sfrom, sto, start, end)</var><a class="copiable-link" href="#index-scm_005fstring_005fxcopy_005fx"> ¶</a></span></dt>
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<dd><p>Exactly the same as <code class="code">xsubstring</code>, but the extracted text
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is written into the string <var class="var">target</var> starting at index
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<var class="var">tstart</var>. The operation is not defined if <code class="code">(eq?
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<var class="var">target</var> <var class="var">s</var>)</code> or these arguments share storage – you
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cannot copy a string on top of itself.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002dreplace"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-replace</strong> <var class="def-var-arguments">s1 s2 [start1 [end1 [start2 [end2]]]]</var><a class="copiable-link" href="#index-string_002dreplace"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fstring_005freplace"><span class="category-def">C Function: </span><span><strong class="def-name">scm_string_replace</strong> <var class="def-var-arguments">(s1, s2, start1, end1, start2, end2)</var><a class="copiable-link" href="#index-scm_005fstring_005freplace"> ¶</a></span></dt>
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<dd><p>Return the string <var class="var">s1</var>, but with the characters
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<var class="var">start1</var> … <var class="var">end1</var> replaced by the characters
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<var class="var">start2</var> … <var class="var">end2</var> from <var class="var">s2</var>.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002dtokenize"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-tokenize</strong> <var class="def-var-arguments">s [token_set [start [end]]]</var><a class="copiable-link" href="#index-string_002dtokenize"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fstring_005ftokenize"><span class="category-def">C Function: </span><span><strong class="def-name">scm_string_tokenize</strong> <var class="def-var-arguments">(s, token_set, start, end)</var><a class="copiable-link" href="#index-scm_005fstring_005ftokenize"> ¶</a></span></dt>
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<dd><p>Split the string <var class="var">s</var> into a list of substrings, where each
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substring is a maximal non-empty contiguous sequence of
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characters from the character set <var class="var">token_set</var>, which
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defaults to <code class="code">char-set:graphic</code>.
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If <var class="var">start</var> or <var class="var">end</var> indices are provided, they restrict
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<code class="code">string-tokenize</code> to operating on the indicated substring
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of <var class="var">s</var>.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002dfilter"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-filter</strong> <var class="def-var-arguments">char_pred s [start [end]]</var><a class="copiable-link" href="#index-string_002dfilter"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fstring_005ffilter"><span class="category-def">C Function: </span><span><strong class="def-name">scm_string_filter</strong> <var class="def-var-arguments">(char_pred, s, start, end)</var><a class="copiable-link" href="#index-scm_005fstring_005ffilter"> ¶</a></span></dt>
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<dd><p>Filter the string <var class="var">s</var>, retaining only those characters which
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satisfy <var class="var">char_pred</var>.
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</p>
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<p>If <var class="var">char_pred</var> is a procedure, it is applied to each character as
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a predicate, if it is a character, it is tested for equality and if it
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is a character set, it is tested for membership.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002ddelete"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-delete</strong> <var class="def-var-arguments">char_pred s [start [end]]</var><a class="copiable-link" href="#index-string_002ddelete"> ¶</a></span></dt>
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<dt class="deffnx def-cmd-deffn" id="index-scm_005fstring_005fdelete"><span class="category-def">C Function: </span><span><strong class="def-name">scm_string_delete</strong> <var class="def-var-arguments">(char_pred, s, start, end)</var><a class="copiable-link" href="#index-scm_005fstring_005fdelete"> ¶</a></span></dt>
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<dd><p>Delete characters satisfying <var class="var">char_pred</var> from <var class="var">s</var>.
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</p>
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<p>If <var class="var">char_pred</var> is a procedure, it is applied to each character as
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a predicate, if it is a character, it is tested for equality and if it
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is a character set, it is tested for membership.
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</p></dd></dl>
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<p>The following additional functions are available in the module
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<code class="code">(ice-9 string-fun)</code>. They can be used with:
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</p>
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<div class="example">
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<pre class="example-preformatted">(use-modules (ice-9 string-fun))
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</pre></div>
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<dl class="first-deffn">
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<dt class="deffn" id="index-string_002dreplace_002dsubstring"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">string-replace-substring</strong> <var class="def-var-arguments">str substring replacement</var><a class="copiable-link" href="#index-string_002dreplace_002dsubstring"> ¶</a></span></dt>
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<dd><p>Return a new string where every instance of <var class="var">substring</var> in string
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<var class="var">str</var> has been replaced by <var class="var">replacement</var>. For example:
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</p>
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<div class="example lisp">
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<pre class="lisp-preformatted">(string-replace-substring "a ring of strings" "ring" "rut")
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⇒ "a rut of struts"
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</pre></div>
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</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="Representing-Strings-as-Bytes.html">Representing Strings as Bytes</a>, Previous: <a href="Mapping-Folding-and-Unfolding.html">Mapping, Folding, and Unfolding</a>, Up: <a href="Strings.html">Strings</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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