293 lines
17 KiB
HTML
293 lines
17 KiB
HTML
|
||
<!DOCTYPE html>
|
||
|
||
<html xmlns="http://www.w3.org/1999/xhtml" lang="zh_CN">
|
||
<head>
|
||
<meta charset="utf-8" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" />
|
||
|
||
<title>linecache --- 随机读写文本行 — Python 3.8.20 文档</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
|
||
|
||
<link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
|
||
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
|
||
|
||
<script id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
|
||
<script src="../_static/jquery.js"></script>
|
||
<script src="../_static/underscore.js"></script>
|
||
<script src="../_static/doctools.js"></script>
|
||
<script src="../_static/language_data.js"></script>
|
||
<script src="../_static/translations.js"></script>
|
||
|
||
<script src="../_static/sidebar.js"></script>
|
||
|
||
<link rel="search" type="application/opensearchdescription+xml"
|
||
title="在 Python 3.8.20 文档 中搜索"
|
||
href="../_static/opensearch.xml"/>
|
||
<link rel="author" title="关于这些文档" href="../about.html" />
|
||
<link rel="index" title="索引" href="../genindex.html" />
|
||
<link rel="search" title="搜索" href="../search.html" />
|
||
<link rel="copyright" title="版权所有" href="../copyright.html" />
|
||
<link rel="next" title="shutil --- 高阶文件操作" href="shutil.html" />
|
||
<link rel="prev" title="fnmatch --- Unix 文件名模式匹配" href="fnmatch.html" />
|
||
<link rel="canonical" href="https://docs.python.org/3/library/linecache.html" />
|
||
|
||
|
||
|
||
|
||
|
||
<style>
|
||
@media only screen {
|
||
table.full-width-table {
|
||
width: 100%;
|
||
}
|
||
}
|
||
</style>
|
||
<link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
|
||
<script type="text/javascript" src="../_static/copybutton.js"></script>
|
||
<script type="text/javascript" src="../_static/menu.js"></script>
|
||
|
||
</head>
|
||
<body>
|
||
<div class="mobile-nav">
|
||
<input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
|
||
aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
|
||
<label for="menuToggler" class="toggler__label">
|
||
<span></span>
|
||
</label>
|
||
<nav class="nav-content" role="navigation">
|
||
<a href="https://www.python.org/" class="nav-logo">
|
||
<img src="../_static/py.svg" alt="Logo"/>
|
||
</a>
|
||
<div class="version_switcher_placeholder"></div>
|
||
<form role="search" class="search" action="../search.html" method="get">
|
||
<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
|
||
<path fill-rule="nonzero"
|
||
d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z" fill="#444"></path>
|
||
</svg>
|
||
<input type="text" name="q" aria-label="快速搜索"/>
|
||
<input type="submit" value="转向"/>
|
||
</form>
|
||
</nav>
|
||
<div class="menu-wrapper">
|
||
<nav class="menu" role="navigation" aria-label="main navigation">
|
||
<div class="language_switcher_placeholder"></div>
|
||
<h4>上一个主题</h4>
|
||
<p class="topless"><a href="fnmatch.html"
|
||
title="上一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">fnmatch</span></code> --- Unix 文件名模式匹配</a></p>
|
||
<h4>下一个主题</h4>
|
||
<p class="topless"><a href="shutil.html"
|
||
title="下一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">shutil</span></code> --- 高阶文件操作</a></p>
|
||
<div role="note" aria-label="source link">
|
||
<h3>本页</h3>
|
||
<ul class="this-page-menu">
|
||
<li><a href="../bugs.html">报告 Bug</a></li>
|
||
<li>
|
||
<a href="https://github.com/python/cpython/blob/3.8/Doc/library/linecache.rst"
|
||
rel="nofollow">显示源代码
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</nav>
|
||
</div>
|
||
</div>
|
||
|
||
<div id="outdated-warning" style="padding: .5em; text-align: center; background-color: #FFBABA; color: #6A0E0E;">
|
||
这个文档所针对的是一个已不再受支持的 Python 旧版本。
|
||
你应当升级版本，并阅读
|
||
<a href="/3/library/linecache.html"> Python 当前稳定版本的文档</a>.
|
||
</div>
|
||
|
||
<div class="related" role="navigation" aria-label="related navigation">
|
||
<h3>导航</h3>
|
||
<ul>
|
||
<li class="right" style="margin-right: 10px">
|
||
<a href="../genindex.html" title="总目录"
|
||
accesskey="I">索引</a></li>
|
||
<li class="right" >
|
||
<a href="../py-modindex.html" title="Python 模块索引"
|
||
>模块</a> |</li>
|
||
<li class="right" >
|
||
<a href="shutil.html" title="shutil --- 高阶文件操作"
|
||
accesskey="N">下一页</a> |</li>
|
||
<li class="right" >
|
||
<a href="fnmatch.html" title="fnmatch --- Unix 文件名模式匹配"
|
||
accesskey="P">上一页</a> |</li>
|
||
|
||
<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
|
||
<li><a href="https://www.python.org/">Python</a> »</li>
|
||
<li class="switchers">
|
||
<div class="language_switcher_placeholder"></div>
|
||
<div class="version_switcher_placeholder"></div>
|
||
</li>
|
||
<li>
|
||
|
||
</li>
|
||
<li id="cpython-language-and-version">
|
||
<a href="../index.html">3.8.20 Documentation</a> »
|
||
</li>
|
||
|
||
<li class="nav-item nav-item-1"><a href="index.html" >Python 标准库</a> »</li>
|
||
<li class="nav-item nav-item-2"><a href="filesys.html" accesskey="U">文件和目录访问</a> »</li>
|
||
<li class="right">
|
||
|
||
|
||
<div class="inline-search" role="search">
|
||
<form class="inline-search" action="../search.html" method="get">
|
||
<input placeholder="快速搜索" aria-label="快速搜索" type="text" name="q" />
|
||
<input type="submit" value="转向" />
|
||
<input type="hidden" name="check_keywords" value="yes" />
|
||
<input type="hidden" name="area" value="default" />
|
||
</form>
|
||
</div>
|
||
|
|
||
</li>
|
||
|
||
</ul>
|
||
</div>
|
||
|
||
<div class="document">
|
||
<div class="documentwrapper">
|
||
<div class="bodywrapper">
|
||
<div class="body" role="main">
|
||
|
||
<section id="module-linecache">
|
||
<span id="linecache-random-access-to-text-lines"></span><h1><a class="reference internal" href="#module-linecache" title="linecache: Provides random access to individual lines from text files."><code class="xref py py-mod docutils literal notranslate"><span class="pre">linecache</span></code></a> --- 随机读写文本行<a class="headerlink" href="#module-linecache" title="永久链接至标题">¶</a></h1>
|
||
<p><strong>源代码:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.8/Lib/linecache.py">Lib/linecache.py</a></p>
|
||
<hr class="docutils" />
|
||
<p><a class="reference internal" href="#module-linecache" title="linecache: Provides random access to individual lines from text files."><code class="xref py py-mod docutils literal notranslate"><span class="pre">linecache</span></code></a> 模块允许从一个 Python 源文件中获取任意的行，并会尝试使用缓存进行内部优化，常应用于从单个文件读取多行的场合。 此模块被 <a class="reference internal" href="traceback.html#module-traceback" title="traceback: Print or retrieve a stack traceback."><code class="xref py py-mod docutils literal notranslate"><span class="pre">traceback</span></code></a> 模块用来提取源码行以便包含在格式化的回溯中。</p>
|
||
<p><a class="reference internal" href="tokenize.html#tokenize.open" title="tokenize.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">tokenize.open()</span></code></a> 函数被用于打开文件。 此函数使用 <a class="reference internal" href="tokenize.html#tokenize.detect_encoding" title="tokenize.detect_encoding"><code class="xref py py-func docutils literal notranslate"><span class="pre">tokenize.detect_encoding()</span></code></a> 来获取文件的编码格式；如果未指明编码格式，则默认编码为 UTF-8。</p>
|
||
<p><a class="reference internal" href="#module-linecache" title="linecache: Provides random access to individual lines from text files."><code class="xref py py-mod docutils literal notranslate"><span class="pre">linecache</span></code></a> 模块定义了下列函数：</p>
|
||
<dl class="function">
|
||
<dt id="linecache.getline">
|
||
<code class="sig-prename descclassname">linecache.</code><code class="sig-name descname">getline</code><span class="sig-paren">(</span><em class="sig-param">filename</em>, <em class="sig-param">lineno</em>, <em class="sig-param">module_globals=None</em><span class="sig-paren">)</span><a class="headerlink" href="#linecache.getline" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>从名为 <em>filename</em> 的文件中获取 <em>lineno</em> 行，此函数绝不会引发异常 --- 出现错误时它将返回 <code class="docutils literal notranslate"><span class="pre">''</span></code> (所有找到的行都将包含换行符作为结束)。</p>
|
||
<p id="index-0">如果找不到名为 <em>filename</em> 的文件，此函数会先在 <em>module_globals</em> 中检查 <span class="target" id="index-3"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0302"><strong>PEP 302</strong></a> <code class="docutils literal notranslate"><span class="pre">__loader__</span></code>。 如果存在这样的加载器并且它定义了 <code class="docutils literal notranslate"><span class="pre">get_source</span></code> 方法，则由该方法来确定源行 (如果 <code class="docutils literal notranslate"><span class="pre">get_source()</span></code> 返回 <code class="docutils literal notranslate"><span class="pre">None</span></code>，则该函数返回 <code class="docutils literal notranslate"><span class="pre">''</span></code>)。 最后，如果 <em>filename</em> 是一个相对路径文件名，则它会在模块搜索路径 <code class="docutils literal notranslate"><span class="pre">sys.path</span></code> 中按条目的相对位置进行查找。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="function">
|
||
<dt id="linecache.clearcache">
|
||
<code class="sig-prename descclassname">linecache.</code><code class="sig-name descname">clearcache</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#linecache.clearcache" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>清空缓存。 如果你不再需要之前使用 <a class="reference internal" href="#linecache.getline" title="linecache.getline"><code class="xref py py-func docutils literal notranslate"><span class="pre">getline()</span></code></a> 从文件读取的行即可使用此函数。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="function">
|
||
<dt id="linecache.checkcache">
|
||
<code class="sig-prename descclassname">linecache.</code><code class="sig-name descname">checkcache</code><span class="sig-paren">(</span><em class="sig-param">filename=None</em><span class="sig-paren">)</span><a class="headerlink" href="#linecache.checkcache" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>检查缓存有效性。 如果缓存中的文件在磁盘上发生了改变，而你需要更新后的版本即可使用此函数。 如果省略了 <em>filename</em>，它会检查缓存中的所有条目。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="function">
|
||
<dt id="linecache.lazycache">
|
||
<code class="sig-prename descclassname">linecache.</code><code class="sig-name descname">lazycache</code><span class="sig-paren">(</span><em class="sig-param">filename</em>, <em class="sig-param">module_globals</em><span class="sig-paren">)</span><a class="headerlink" href="#linecache.lazycache" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>捕获有关某个非基于文件的模块的足够细节信息，以允许稍后再通过 <a class="reference internal" href="#linecache.getline" title="linecache.getline"><code class="xref py py-func docutils literal notranslate"><span class="pre">getline()</span></code></a> 来获取其中的行，即使当稍后调用时 <em>module_globals</em> 为 <code class="docutils literal notranslate"><span class="pre">None</span></code>。 这可以避免在实际需要读取行之前执行 I/O，也不必始终保持模块全局变量。</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">3.5 新版功能.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<p>示例:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">linecache</span>
|
||
<span class="gp">>>> </span><span class="n">linecache</span><span class="o">.</span><span class="n">getline</span><span class="p">(</span><span class="n">linecache</span><span class="o">.</span><span class="vm">__file__</span><span class="p">,</span> <span class="mi">8</span><span class="p">)</span>
|
||
<span class="go">'import sys\n'</span>
|
||
</pre></div>
|
||
</div>
|
||
</section>
|
||
|
||
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
|
||
<div class="sphinxsidebarwrapper">
|
||
<h4>上一个主题</h4>
|
||
<p class="topless"><a href="fnmatch.html"
|
||
title="上一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">fnmatch</span></code> --- Unix 文件名模式匹配</a></p>
|
||
<h4>下一个主题</h4>
|
||
<p class="topless"><a href="shutil.html"
|
||
title="下一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">shutil</span></code> --- 高阶文件操作</a></p>
|
||
<div role="note" aria-label="source link">
|
||
<h3>本页</h3>
|
||
<ul class="this-page-menu">
|
||
<li><a href="../bugs.html">报告 Bug</a></li>
|
||
<li>
|
||
<a href="https://github.com/python/cpython/blob/3.8/Doc/library/linecache.rst"
|
||
rel="nofollow">显示源代码
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="clearer"></div>
|
||
</div>
|
||
<div class="related" role="navigation" aria-label="related navigation">
|
||
<h3>导航</h3>
|
||
<ul>
|
||
<li class="right" style="margin-right: 10px">
|
||
<a href="../genindex.html" title="总目录"
|
||
>索引</a></li>
|
||
<li class="right" >
|
||
<a href="../py-modindex.html" title="Python 模块索引"
|
||
>模块</a> |</li>
|
||
<li class="right" >
|
||
<a href="shutil.html" title="shutil --- 高阶文件操作"
|
||
>下一页</a> |</li>
|
||
<li class="right" >
|
||
<a href="fnmatch.html" title="fnmatch --- Unix 文件名模式匹配"
|
||
>上一页</a> |</li>
|
||
|
||
<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
|
||
<li><a href="https://www.python.org/">Python</a> »</li>
|
||
<li class="switchers">
|
||
<div class="language_switcher_placeholder"></div>
|
||
<div class="version_switcher_placeholder"></div>
|
||
</li>
|
||
<li>
|
||
|
||
</li>
|
||
<li id="cpython-language-and-version">
|
||
<a href="../index.html">3.8.20 Documentation</a> »
|
||
</li>
|
||
|
||
<li class="nav-item nav-item-1"><a href="index.html" >Python 标准库</a> »</li>
|
||
<li class="nav-item nav-item-2"><a href="filesys.html" >文件和目录访问</a> »</li>
|
||
<li class="right">
|
||
|
||
|
||
<div class="inline-search" role="search">
|
||
<form class="inline-search" action="../search.html" method="get">
|
||
<input placeholder="快速搜索" aria-label="快速搜索" type="text" name="q" />
|
||
<input type="submit" value="转向" />
|
||
<input type="hidden" name="check_keywords" value="yes" />
|
||
<input type="hidden" name="area" value="default" />
|
||
</form>
|
||
</div>
|
||
|
|
||
</li>
|
||
|
||
</ul>
|
||
</div>
|
||
<div class="footer">
|
||
© <a href="../copyright.html">版权所有</a> 2001-2024, Python Software Foundation.
|
||
<br />
|
||
This page is licensed under the Python Software Foundation License Version 2.
|
||
<br />
|
||
Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
|
||
<br />
|
||
|
||
<br />
|
||
|
||
The Python Software Foundation is a non-profit corporation.
|
||
<a href="https://www.python.org/psf/donations/">Please donate.</a>
|
||
<br />
|
||
<br />
|
||
|
||
最后更新于 12月 09, 2024.
|
||
<a href="https://docs.python.org/3/bugs.html">Found a bug</a>?
|
||
<br />
|
||
|
||
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 2.4.4.
|
||
</div>
|
||
|
||
</body>
|
||
</html> |