Edit File: api-text-misc.html
<!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="Content-Type" content="text/html; charset=utf-8" /> <title>Miscellaneous functions for manipulating text — kitchen 1.1.1 documentation</title> <link rel="stylesheet" href="_static/default.css" type="text/css" /> <link rel="stylesheet" href="_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '', VERSION: '1.1.1', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </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> <link rel="search" type="application/opensearchdescription+xml" title="Search within kitchen 1.1.1 documentation" href="_static/opensearch.xml"/> <link rel="top" title="kitchen 1.1.1 documentation" href="index.html" /> <link rel="up" title="Kitchen.text: unicode and utf8 and xml oh my!" href="api-text.html" /> <link rel="next" title="UTF-8" href="api-text-utf8.html" /> <link rel="prev" title="Format Text for Display" href="api-text-display.html" /> </head> <body> <div class="related"> <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="api-text-utf8.html" title="UTF-8" accesskey="N">next</a> |</li> <li class="right" > <a href="api-text-display.html" title="Format Text for Display" accesskey="P">previous</a> |</li> <li><a href="index.html">kitchen 1.1.1 documentation</a> »</li> <li><a href="api-overview.html" >Kitchen API</a> »</li> <li><a href="api-text.html" accesskey="U">Kitchen.text: unicode and utf8 and xml oh my!</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <span class="target" id="module-kitchen.text.misc"></span><div class="section" id="miscellaneous-functions-for-manipulating-text"> <h1>Miscellaneous functions for manipulating text<a class="headerlink" href="#miscellaneous-functions-for-manipulating-text" title="Permalink to this headline">¶</a></h1> <p>Collection of text functions that don’t fit in another category.</p> <dl class="function"> <dt id="kitchen.text.misc.byte_string_valid_encoding"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">byte_string_valid_encoding</tt><big>(</big><em>byte_string</em>, <em>encoding='utf-8'</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.byte_string_valid_encoding" title="Permalink to this definition">¶</a></dt> <dd><p>Detect if a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> is valid in a specific encoding</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple"> <li><strong>byte_string</strong> – Byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> to test for bytes not valid in this encoding</li> <li><strong>encoding</strong> – encoding to test against. Defaults to <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">UTF-8</em></a>.</li> </ul> </td> </tr> <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last"><a class="reference external" href="http://docs.python.org/library/constants.html#True" title="(in Python v2.7)"><tt class="xref py py-data docutils literal"><span class="pre">True</span></tt></a> if there are no invalid <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">UTF-8</em></a> characters. <a class="reference external" href="http://docs.python.org/library/constants.html#False" title="(in Python v2.7)"><tt class="xref py py-data docutils literal"><span class="pre">False</span></tt></a> if an invalid character is detected.</p> </td> </tr> </tbody> </table> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">This function checks whether the byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> is valid in the specified encoding. It <strong>does not</strong> detect whether the byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> actually was encoded in that encoding. If you want that sort of functionality, you probably want to use <a class="reference internal" href="#kitchen.text.misc.guess_encoding" title="kitchen.text.misc.guess_encoding"><tt class="xref py py-func docutils literal"><span class="pre">guess_encoding()</span></tt></a> instead.</p> </div> </dd></dl> <dl class="function"> <dt id="kitchen.text.misc.byte_string_valid_xml"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">byte_string_valid_xml</tt><big>(</big><em>byte_string</em>, <em>encoding='utf-8'</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.byte_string_valid_xml" title="Permalink to this definition">¶</a></dt> <dd><p>Check that a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> would be valid in xml</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple"> <li><strong>byte_string</strong> – Byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> to check</li> <li><strong>encoding</strong> – Encoding of the xml file. Default: <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">UTF-8</em></a></li> </ul> </td> </tr> <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last"><a class="reference external" href="http://docs.python.org/library/constants.html#True" title="(in Python v2.7)"><tt class="xref py py-data docutils literal"><span class="pre">True</span></tt></a> if the string is valid. <a class="reference external" href="http://docs.python.org/library/constants.html#False" title="(in Python v2.7)"><tt class="xref py py-data docutils literal"><span class="pre">False</span></tt></a> if it would be invalid in the xml file</p> </td> </tr> </tbody> </table> <p>In some cases you’ll have a whole bunch of byte strings and rather than transforming them to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> and back to byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> for output to xml, you will just want to make sure they work with the xml file you’re constructing. This function will help you do that. Example:</p> <div class="highlight-python"><div class="highlight"><pre><span class="n">ARRAY_OF_MOSTLY_UTF8_STRINGS</span> <span class="o">=</span> <span class="p">[</span><span class="o">...</span><span class="p">]</span> <span class="n">processed_array</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">for</span> <span class="n">string</span> <span class="ow">in</span> <span class="n">ARRAY_OF_MOSTLY_UTF8_STRINGS</span><span class="p">:</span> <span class="k">if</span> <span class="n">byte_string_valid_xml</span><span class="p">(</span><span class="n">string</span><span class="p">,</span> <span class="s">'utf-8'</span><span class="p">):</span> <span class="n">processed_array</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">string</span><span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="n">processed_array</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">guess_bytes_to_xml</span><span class="p">(</span><span class="n">string</span><span class="p">,</span> <span class="n">encoding</span><span class="o">=</span><span class="s">'utf-8'</span><span class="p">))</span> <span class="n">output_xml</span><span class="p">(</span><span class="n">processed_array</span><span class="p">)</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="kitchen.text.misc.guess_encoding"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">guess_encoding</tt><big>(</big><em>byte_string</em>, <em>disable_chardet=False</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.guess_encoding" title="Permalink to this definition">¶</a></dt> <dd><p>Try to guess the encoding of a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt></p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple"> <li><strong>byte_string</strong> – byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> to guess the encoding of</li> <li><strong>disable_chardet</strong> – If this is True, we never attempt to use <tt class="xref py py-mod docutils literal"><span class="pre">chardet</span></tt> to guess the encoding. This is useful if you need to have reproducibility whether <tt class="xref py py-mod docutils literal"><span class="pre">chardet</span></tt> is installed or not. Default: <a class="reference external" href="http://docs.python.org/library/constants.html#False" title="(in Python v2.7)"><tt class="xref py py-data docutils literal"><span class="pre">False</span></tt></a>.</li> </ul> </td> </tr> <tr class="field-even field"><th class="field-name" colspan="2">Raises TypeError:</th></tr> <tr class="field-even field"><td> </td><td class="field-body"><p class="first">if <tt class="xref py py-attr docutils literal"><span class="pre">byte_string</span></tt> is not a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> type</p> </td> </tr> <tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last">string containing a guess at the encoding of <tt class="xref py py-attr docutils literal"><span class="pre">byte_string</span></tt>. This is appropriate to pass as the encoding argument when encoding and decoding unicode strings.</p> </td> </tr> </tbody> </table> <p>We start by attempting to decode the byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> as <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">UTF-8</em></a>. If this succeeds we tell the world it’s <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">UTF-8</em></a> text. If it doesn’t and <tt class="xref py py-mod docutils literal"><span class="pre">chardet</span></tt> is installed on the system and <tt class="xref py py-attr docutils literal"><span class="pre">disable_chardet</span></tt> is False this function will use it to try detecting the encoding of <tt class="xref py py-attr docutils literal"><span class="pre">byte_string</span></tt>. If it is not installed or <tt class="xref py py-mod docutils literal"><span class="pre">chardet</span></tt> cannot determine the encoding with a high enough confidence then we rather arbitrarily claim that it is <tt class="docutils literal"><span class="pre">latin-1</span></tt>. Since <tt class="docutils literal"><span class="pre">latin-1</span></tt> will encode to every byte, decoding from <tt class="docutils literal"><span class="pre">latin-1</span></tt> to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> will not cause <tt class="xref py py-exc docutils literal"><span class="pre">UnicodeErrors</span></tt> although the output might be mangled.</p> </dd></dl> <dl class="function"> <dt id="kitchen.text.misc.html_entities_unescape"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">html_entities_unescape</tt><big>(</big><em>string</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.html_entities_unescape" title="Permalink to this definition">¶</a></dt> <dd><p>Substitute unicode characters for HTML entities</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>string</strong> – <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string to substitute out html entities</td> </tr> <tr class="field-even field"><th class="field-name" colspan="2">Raises TypeError:</th></tr> <tr class="field-even field"><td> </td><td class="field-body">if something other than a <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string is given</td> </tr> <tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string</td> </tr> <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">The plain text without html entities</td> </tr> </tbody> </table> </dd></dl> <dl class="function"> <dt id="kitchen.text.misc.process_control_chars"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">process_control_chars</tt><big>(</big><em>string</em>, <em>strategy='replace'</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.process_control_chars" title="Permalink to this definition">¶</a></dt> <dd><p>Look for and transform <a class="reference internal" href="glossary.html#term-control-characters"><em class="xref std std-term">control characters</em></a> in a string</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple"> <li><strong>string</strong> – string to search for and transform <a class="reference internal" href="glossary.html#term-control-characters"><em class="xref std std-term">control characters</em></a> within</li> <li><strong>strategy</strong> – <p>XML does not allow <a class="reference internal" href="glossary.html#term-ascii"><em class="xref std std-term">ASCII</em></a> <a class="reference internal" href="glossary.html#term-control-characters"><em class="xref std std-term">control characters</em></a>. When we encounter those we need to know what to do. Valid options are:</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">replace:</th><td class="field-body">(default) Replace the <a class="reference internal" href="glossary.html#term-control-characters"><em class="xref std std-term">control characters</em></a> with <tt class="docutils literal"><span class="pre">"?"</span></tt></td> </tr> <tr class="field-even field"><th class="field-name">ignore:</th><td class="field-body">Remove the characters altogether from the output</td> </tr> <tr class="field-odd field"><th class="field-name">strict:</th><td class="field-body">Raise a <a class="reference internal" href="api-exceptions.html#kitchen.text.exceptions.ControlCharError" title="kitchen.text.exceptions.ControlCharError"><tt class="xref py py-exc docutils literal"><span class="pre">ControlCharError</span></tt></a> when we encounter a control character</td> </tr> </tbody> </table> </li> </ul> </td> </tr> <tr class="field-even field"><th class="field-name">Raises:</th><td class="field-body"><ul class="first simple"> <li><strong>TypeError</strong> – if <tt class="xref py py-attr docutils literal"><span class="pre">string</span></tt> is not a unicode string.</li> <li><strong>ValueError</strong> – if the strategy is not one of replace, ignore, or strict.</li> <li><a class="reference internal" href="api-exceptions.html#kitchen.text.exceptions.ControlCharError" title="kitchen.text.exceptions.ControlCharError"><strong>kitchen.text.exceptions.ControlCharError</strong></a> – if the strategy is <tt class="docutils literal"><span class="pre">strict</span></tt> and a <a class="reference internal" href="glossary.html#term-control-character"><em class="xref std std-term">control character</em></a> is present in the <tt class="xref py py-attr docutils literal"><span class="pre">string</span></tt></li> </ul> </td> </tr> <tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last"><tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string with no <a class="reference internal" href="glossary.html#term-control-characters"><em class="xref std std-term">control characters</em></a> in it.</p> </td> </tr> </tbody> </table> </dd></dl> <dl class="function"> <dt id="kitchen.text.misc.str_eq"> <tt class="descclassname">kitchen.text.misc.</tt><tt class="descname">str_eq</tt><big>(</big><em>str1</em>, <em>str2</em>, <em>encoding='utf-8'</em>, <em>errors='replace'</em><big>)</big><a class="headerlink" href="#kitchen.text.misc.str_eq" title="Permalink to this definition">¶</a></dt> <dd><p>Compare two stringsi, converting to byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> if one is <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt></p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple"> <li><strong>str1</strong> – First string to compare</li> <li><strong>str2</strong> – Second string to compare</li> <li><strong>encoding</strong> – If we need to convert one string into a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> to compare, the encoding to use. Default is <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">utf-8</em></a>.</li> <li><strong>errors</strong> – What to do if we encounter errors when encoding the string. See the <a class="reference internal" href="api-text-converters.html#kitchen.text.converters.to_bytes" title="kitchen.text.converters.to_bytes"><tt class="xref py py-func docutils literal"><span class="pre">kitchen.text.converters.to_bytes()</span></tt></a> documentation for possible values. The default is <tt class="docutils literal"><span class="pre">replace</span></tt>.</li> </ul> </td> </tr> </tbody> </table> <p>This function prevents <tt class="xref py py-exc docutils literal"><span class="pre">UnicodeError</span></tt> (python-2.4 or less) and <tt class="xref py py-exc docutils literal"><span class="pre">UnicodeWarning</span></tt> (python 2.5 and higher) when we compare a <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string to a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt>. The errors normally arise because the conversion is done to <a class="reference internal" href="glossary.html#term-ascii"><em class="xref std std-term">ASCII</em></a>. This function lets you convert to <a class="reference internal" href="glossary.html#term-utf-8"><em class="xref std std-term">utf-8</em></a> or another encoding instead.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">When we need to convert one of the strings from <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> in order to compare them we convert the <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string into a byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt>. That means that strings can compare differently if you use different encodings for each.</p> </div> <p>Note that <tt class="docutils literal"><span class="pre">str1</span> <span class="pre">==</span> <span class="pre">str2</span></tt> is faster than this function if you can accept the following limitations:</p> <ul class="simple"> <li>Limited to python-2.5+ (otherwise a <tt class="xref py py-exc docutils literal"><span class="pre">UnicodeDecodeError</span></tt> may be thrown)</li> <li>Will generate a <tt class="xref py py-exc docutils literal"><span class="pre">UnicodeWarning</span></tt> if non-<a class="reference internal" href="glossary.html#term-ascii"><em class="xref std std-term">ASCII</em></a> byte <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> is compared to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> string.</li> </ul> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="api-text-display.html" title="previous chapter">Format Text for Display</a></p> <h4>Next topic</h4> <p class="topless"><a href="api-text-utf8.html" title="next chapter">UTF-8</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="_sources/api-text-misc.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="api-text-utf8.html" title="UTF-8" >next</a> |</li> <li class="right" > <a href="api-text-display.html" title="Format Text for Display" >previous</a> |</li> <li><a href="index.html">kitchen 1.1.1 documentation</a> »</li> <li><a href="api-overview.html" >Kitchen API</a> »</li> <li><a href="api-text.html" >Kitchen.text: unicode and utf8 and xml oh my!</a> »</li> </ul> </div> <div class="footer"> © Copyright 2011 Red Hat, Inc. and others. 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