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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>7.10. stringprep — Internet String Preparation — Python 2.7.16 documentation</title> <link rel="stylesheet" href="../_static/classic.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.16 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="7.11. fpformat — Floating point conversions" href="fpformat.html" /> <link rel="prev" title="7.9. unicodedata — Unicode Database" href="unicodedata.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/2/library/stringprep.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="fpformat.html" title="7.11. fpformat — Floating point conversions" accesskey="N">next</a> |</li> <li class="right" > <a href="unicodedata.html" title="7.9. unicodedata — Unicode Database" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.16 documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="strings.html" accesskey="U">7. String Services</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-stringprep"> <span id="stringprep-internet-string-preparation"></span><h1>7.10. <a class="reference internal" href="#module-stringprep" title="stringprep: String preparation, as per RFC 3453"><code class="xref py py-mod docutils literal notranslate"><span class="pre">stringprep</span></code></a> — Internet String Preparation<a class="headerlink" href="#module-stringprep" title="Permalink to this headline">¶</a></h1> <div class="versionadded"> <p><span class="versionmodified">New in version 2.3.</span></p> </div> <p>When identifying things (such as host names) in the internet, it is often necessary to compare such identifications for “equality”. Exactly how this comparison is executed may depend on the application domain, e.g. whether it should be case-insensitive or not. It may be also necessary to restrict the possible identifications, to allow only identifications consisting of “printable” characters.</p> <p><span class="target" id="index-0"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc3454.html"><strong>RFC 3454</strong></a> defines a procedure for “preparing” Unicode strings in internet protocols. Before passing strings onto the wire, they are processed with the preparation procedure, after which they have a certain normalized form. The RFC defines a set of tables, which can be combined into profiles. Each profile must define which tables it uses, and what other optional parts of the <code class="docutils literal notranslate"><span class="pre">stringprep</span></code> procedure are part of the profile. One example of a <code class="docutils literal notranslate"><span class="pre">stringprep</span></code> profile is <code class="docutils literal notranslate"><span class="pre">nameprep</span></code>, which is used for internationalized domain names.</p> <p>The module <a class="reference internal" href="#module-stringprep" title="stringprep: String preparation, as per RFC 3453"><code class="xref py py-mod docutils literal notranslate"><span class="pre">stringprep</span></code></a> only exposes the tables from RFC 3454. As these tables would be very large to represent them as dictionaries or lists, the module uses the Unicode character database internally. The module source code itself was generated using the <code class="docutils literal notranslate"><span class="pre">mkstringprep.py</span></code> utility.</p> <p>As a result, these tables are exposed as functions, not as data structures. There are two kinds of tables in the RFC: sets and mappings. For a set, <a class="reference internal" href="#module-stringprep" title="stringprep: String preparation, as per RFC 3453"><code class="xref py py-mod docutils literal notranslate"><span class="pre">stringprep</span></code></a> provides the “characteristic function”, i.e. a function that returns true if the parameter is part of the set. For mappings, it provides the mapping function: given the key, it returns the associated value. Below is a list of all functions available in the module.</p> <dl class="function"> <dt id="stringprep.in_table_a1"> <code class="descclassname">stringprep.</code><code class="descname">in_table_a1</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_a1" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableA.1 (Unassigned code points in Unicode 3.2).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_b1"> <code class="descclassname">stringprep.</code><code class="descname">in_table_b1</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_b1" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableB.1 (Commonly mapped to nothing).</p> </dd></dl> <dl class="function"> <dt id="stringprep.map_table_b2"> <code class="descclassname">stringprep.</code><code class="descname">map_table_b2</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.map_table_b2" title="Permalink to this definition">¶</a></dt> <dd><p>Return the mapped value for <em>code</em> according to tableB.2 (Mapping for case-folding used with NFKC).</p> </dd></dl> <dl class="function"> <dt id="stringprep.map_table_b3"> <code class="descclassname">stringprep.</code><code class="descname">map_table_b3</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.map_table_b3" title="Permalink to this definition">¶</a></dt> <dd><p>Return the mapped value for <em>code</em> according to tableB.3 (Mapping for case-folding used with no normalization).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c11"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c11</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c11" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.1.1 (ASCII space characters).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c12"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c12</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c12" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.1.2 (Non-ASCII space characters).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c11_c12"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c11_c12</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c11_c12" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.1 (Space characters, union of C.1.1 and C.1.2).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c21"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c21</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c21" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.2.1 (ASCII control characters).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c22"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c22</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c22" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.2.2 (Non-ASCII control characters).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c21_c22"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c21_c22</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c21_c22" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.2 (Control characters, union of C.2.1 and C.2.2).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c3"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c3</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c3" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.3 (Private use).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c4"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c4</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c4" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.4 (Non-character code points).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c5"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c5</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c5" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.5 (Surrogate codes).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c6"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c6</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c6" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.6 (Inappropriate for plain text).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c7"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c7</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c7" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.7 (Inappropriate for canonical representation).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c8"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c8</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c8" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.8 (Change display properties or are deprecated).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_c9"> <code class="descclassname">stringprep.</code><code class="descname">in_table_c9</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_c9" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableC.9 (Tagging characters).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_d1"> <code class="descclassname">stringprep.</code><code class="descname">in_table_d1</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_d1" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableD.1 (Characters with bidirectional property “R” or “AL”).</p> </dd></dl> <dl class="function"> <dt id="stringprep.in_table_d2"> <code class="descclassname">stringprep.</code><code class="descname">in_table_d2</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span><a class="headerlink" href="#stringprep.in_table_d2" title="Permalink to this definition">¶</a></dt> <dd><p>Determine whether <em>code</em> is in tableD.2 (Characters with bidirectional property “L”).</p> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="unicodedata.html" title="previous chapter">7.9. <code class="docutils literal notranslate"><span class="pre">unicodedata</span></code> — Unicode Database</a></p> <h4>Next topic</h4> <p class="topless"><a href="fpformat.html" title="next chapter">7.11. <code class="docutils literal notranslate"><span class="pre">fpformat</span></code> — Floating point conversions</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> 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