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<html><head><title>基础语法</title><meta charSet="utf-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0"/><meta property="og:title" content="基础语法"/><meta property="og:description" content="Python 基础语法."/><meta property="og:image" content="https://wiki.7wate.com/static/og-image.png"/><meta property="og:width" content="1200"/><meta property="og:height" content="675"/><link rel="icon" href="../../../../static/icon.png"/><meta name="description" content="Python 基础语法."/><meta name="generator" content="Quartz"/><link rel="preconnect" href="https://fonts.googleapis.com"/><link rel="preconnect" href="https://fonts.gstatic.com"/><script async src="https://umami.7wate.com/script.js" data-website-id="c061efdc-95dd-4d21-9d04-a1ffda0a85b9"></script><script>
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</script><link href="../../../../index.css" rel="stylesheet" type="text/css" spa-preserve/><link href="https://cdn.jsdelivr.net/npm/katex@0.16.0/dist/katex.min.css" rel="stylesheet" type="text/css" spa-preserve/><link href="https://fonts.googleapis.com/css2?family=IBM Plex Mono&family=Schibsted Grotesk:wght@400;700&family=Source Sans Pro:ital,wght@0,400;0,600;1,400;1,600&display=swap" rel="stylesheet" type="text/css" spa-preserve/><script src="../../../../prescript.js" type="application/javascript" spa-preserve></script><script type="application/javascript" spa-preserve>const fetchData = fetch(`../../../../static/contentIndex.json`).then(data => data.json())</script></head><body data-slug="Tech/programming-language/Python/入门/基础语法"><div id="quartz-root" class="page"><div id="quartz-body"><div class="left sidebar"><h1 class="page-title "><a href="../../../..">📚 X·Eden</a></h1><div class="spacer mobile-only"></div><div class="search "><div id="search-icon"><p>Search</p><div></div><svg tabIndex="0" aria-labelledby="title desc" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 19.9 19.7"><title id="title">Search</title><desc id="desc">Search</desc><g class="search-path" fill="none"><path stroke-linecap="square" d="M18.5 18.3l-5.4-5.4"></path><circle cx="8" cy="8" r="7"></circle></g></svg></div><div id="search-container"><div id="search-space"><input autocomplete="off" id="search-bar" name="search" type="text" aria-label="Search for something" placeholder="Search for something"/><div id="results-container"></div></div></div></div><div class="darkmode "><input class="toggle" id="darkmode-toggle" type="checkbox" tabIndex="-1"/><label id="toggle-label-light" for="darkmode-toggle" tabIndex="-1"><svg xmlns="http://www.w3.org/2000/svg" xmlnsXlink="http://www.w3.org/1999/xlink" version="1.1" id="dayIcon" x="0px" y="0px" viewBox="0 0 35 35" style="enable-background:new 0 0 35 35;" xmlSpace="preserve"><title>Light mode</title><path d="M6,17.5C6,16.672,5.328,16,4.5,16h-3C0.672,16,0,16.672,0,17.5 S0.672,19,1.5,19h3C5.328,19,6,18.328,6,17.5z M7.5,26c-0.414,0-0.789,0.168-1.061,0.439l-2,2C4.168,28.711,4,29.086,4,29.5 C4,30.328,4.671,31,5.5,31c0.414,0,0.789-0.168,1.06-0.44l2-2C8.832,28.289,9,27.914,9,27.5C9,26.672,8.329,26,7.5,26z M17.5,6 C18.329,6,19,5.328,19,4.5v-3C19,0.672,18.329,0,17.5,0S16,0.672,16,1.5v3C16,5.328,16.671,6,17.5,6z M27.5,9 c0.414,0,0.789-0.168,1.06-0.439l2-2C30.832,6.289,31,5.914,31,5.5C31,4.672,30.329,4,29.5,4c-0.414,0-0.789,0.168-1.061,0.44 l-2,2C26.168,6.711,26,7.086,26,7.5C26,8.328,26.671,9,27.5,9z M6.439,8.561C6.711,8.832,7.086,9,7.5,9C8.328,9,9,8.328,9,7.5 c0-0.414-0.168-0.789-0.439-1.061l-2-2C6.289,4.168,5.914,4,5.5,4C4.672,4,4,4.672,4,5.5c0,0.414,0.168,0.789,0.439,1.06 L6.439,8.561z M33.5,16h-3c-0.828,0-1.5,0.672-1.5,1.5s0.672,1.5,1.5,1.5h3c0.828,0,1.5-0.672,1.5-1.5S34.328,16,33.5,16z M28.561,26.439C28.289,26.168,27.914,26,27.5,26c-0.828,0-1.5,0.672-1.5,1.5c0,0.414,0.168,0.789,0.439,1.06l2,2 C28.711,30.832,29.086,31,29.5,31c0.828,0,1.5-0.672,1.5-1.5c0-0.414-0.168-0.789-0.439-1.061L28.561,26.439z M17.5,29 c-0.829,0-1.5,0.672-1.5,1.5v3c0,0.828,0.671,1.5,1.5,1.5s1.5-0.672,1.5-1.5v-3C19,29.672,18.329,29,17.5,29z M17.5,7 C11.71,7,7,11.71,7,17.5S11.71,28,17.5,28S28,23.29,28,17.5S23.29,7,17.5,7z M17.5,25c-4.136,0-7.5-3.364-7.5-7.5 c0-4.136,3.364-7.5,7.5-7.5c4.136,0,7.5,3.364,7.5,7.5C25,21.636,21.636,25,17.5,25z"></path></svg></label><label id="toggle-label-dark" for="darkmode-toggle" tabIndex="-1"><svg xmlns="http://www.w3.org/2000/svg" xmlnsXlink="http://www.w3.org/1999/xlink" version="1.1" id="nightIcon" x="0px" y="0px" viewBox="0 0 100 100" style="enable-background='new 0 0 100 100'" xmlSpace="preserve"><title>Dark mode</title><path d="M96.76,66.458c-0.853-0.852-2.15-1.064-3.23-0.534c-6.063,2.991-12.858,4.571-19.655,4.571 C62.022,70.495,50.88,65.88,42.5,57.5C29.043,44.043,25.658,23.536,34.076,6.47c0.532-1.08,0.318-2.379-0.534-3.23 c-0.851-0.852-2.15-1.064-3.23-0.534c-4.918,2.427-9.375,5.619-13.246,9.491c-9.447,9.447-14.65,22.008-14.65
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<p>Python 是一门易于学习、功能强大的编程语言。同时是一种<strong>解释型语言，不需要编译和链接</strong>，可以节省大量开发时间。Python 入门相对其它程序设计语言简单，但是熟练掌握需要一定学习时间，尤其是丰富的魔术方法。</p>
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<p>Python 程序<strong>简洁、易读，通常</strong>比实现同种功能的 C、C++、Java 代码短很多，原因如下：</p>
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<ul>
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<li>高级数据类型允许在单一语句中表述复杂操作；</li>
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<li>使用缩进，而不是括号实现代码块分组；</li>
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<li>无需预声明变量或参数。</li>
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</ul>
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<p>Python 解释器<strong>易于扩展</strong>，使用 C 或 C++（或其他 C 能调用的语言）即可为 Python 扩展新功能和数据类型。Python 也可用作定制软件中的扩展程序语言。</p>
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<p>Python 官网上免费提供了 Python 解释器和扩展的标准库，包括源码和适用于各操作系统的机器码形式，并可自由地分发。</p>
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<p>Python 官网还包含许多<strong>免费丰富的第三方 Python 模块</strong>、程序和工具发布包及文档链接。</p>
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<h2 id="使用">使用<a aria-hidden="true" tabindex="-1" href="#使用" class="internal"> §</a></h2>
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<h3 id="安装">安装<a aria-hidden="true" tabindex="-1" href="#安装" class="internal"> §</a></h3>
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<p>Python 官网：<a href="https://www.python.org/" class="external">https://www.python.org/</a>，可以在 <a href="https://docs.python.org/" class="external">官方文档</a> 帮助下选择合适版本安装。</p>
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<h3 id="运行">运行<a aria-hidden="true" tabindex="-1" href="#运行" class="internal"> §</a></h3>
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<p>Python 安装后在 Shell 中输入 Python 既可运行交互解释器，在解释器内编写 Python 脚本既可以运行。如果需要退出，输入 <code>quit()</code>。</p>
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<h2 id="编码">编码<a aria-hidden="true" tabindex="-1" href="#编码" class="internal"> §</a></h2>
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<p>Python 源码文件的<strong>默认编码是 UTF-8</strong>，如果不使用默认编码，则要声明文件的编码，文件的<strong>第一行</strong>要写成特殊注释。句法如下：</p>
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<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-token-comment);"># -*- coding: encoding -*-</span></span></code></pre></div>
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<h2 id="注释">注释<a aria-hidden="true" tabindex="-1" href="#注释" class="internal"> §</a></h2>
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<ul>
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<li>
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<p>单行注释：以 # 和空格开头的部分</p>
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</li>
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<li>
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<p>多行注释：三个引号开头，三个引号结尾</p>
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</li>
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</ul>
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<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-token-comment);">"""</span></span>
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<span data-line><span style="color:var(--shiki-token-comment);">第一个 Python 程序 - hello, world!</span></span>
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<span data-line><span style="color:var(--shiki-token-comment);">向伟大的 Dennis M. Ritchie 先生致敬</span></span>
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<span data-line><span style="color:var(--shiki-token-comment);">"""</span></span>
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<span data-line><span style="color:var(--shiki-token-comment);"># hello world！</span></span>
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<span data-line><span style="color:var(--shiki-token-function);">print</span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">'hello, world!'</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-token-function);">print</span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"你好, 世界！"</span><span style="color:var(--shiki-token-punctuation);">)</span></span></code></pre></div>
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<h2 id="缩进">缩进<a aria-hidden="true" tabindex="-1" href="#缩进" class="internal"> §</a></h2>
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<p>Python 最具特色的就是使用缩进来表示代码块，不需要使用大括号 <strong>{}</strong> 。缩进的空格数是可变的，但是同一个代码块的语句必须包含相同的缩进空格数。如果语句缩进数的空格数不一致，会导致运行错误。</p>
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<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-token-comment);"># 正确缩进</span></span>
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<span data-line><span style="color:var(--shiki-token-keyword);">if</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-constant);">True</span><span style="color:var(--shiki-token-punctuation);">:</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"True"</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-token-keyword);">else</span><span style="color:var(--shiki-token-punctuation);">:</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"False"</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span></span>
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<span data-line><span style="color:var(--shiki-token-comment);"># 错误缩进</span></span>
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<span data-line><span style="color:var(--shiki-token-keyword);">if</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-constant);">True</span><span style="color:var(--shiki-token-punctuation);">:</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"Answer"</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"True"</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-token-keyword);">else</span><span style="color:var(--shiki-token-punctuation);">:</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"Answer"</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-function);">print </span><span style="color:var(--shiki-token-punctuation);">(</span><span style="color:var(--shiki-token-string-expression);">"False"</span><span style="color:var(--shiki-token-punctuation);">)</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-comment);"># 缩进不一致，会导致运行错误</span></span></code></pre></div>
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<h2 id="行语句">行语句<a aria-hidden="true" tabindex="-1" href="#行语句" class="internal"> §</a></h2>
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<p>如果语句很长，我们可以使用反斜杠 <strong>\</strong> 来实现多行语句；如果在同一行中使用多条语句，语句之间使用分号 <strong>;</strong> 分割。<strong>在 [], {}, 或 () 中的多行语句，不需要使用反斜杠 \。</strong> 字符串之间不换行则会自动拼接。</p>
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<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-token-comment);"># 反斜杠 \ 用法</span></span>
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<span data-line><span style="color:var(--shiki-color-text);">total </span><span style="color:var(--shiki-token-keyword);">=</span><span style="color:var(--shiki-color-text);"> item_one </span><span style="color:var(--shiki-token-keyword);">+</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-punctuation);">\</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> item_two </span><span style="color:var(--shiki-token-keyword);">+</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-punctuation);">\</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> item_three</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span></span>
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<span data-line><span style="color:var(--shiki-token-comment);"># 分号 ; 用法</span></span>
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<span data-line><span style="color:var(--shiki-token-keyword);">import</span><span style="color:var(--shiki-color-text);"> sys; x = </span><span style="color:var(--shiki-token-string-expression);">'runoob'</span><span style="color:var(--shiki-color-text);">; sys</span><span style="color:var(--shiki-token-punctuation);">.</span><span style="color:var(--shiki-color-text);">stdout</span><span style="color:var(--shiki-token-punctuation);">.</span><span style="color:var(--shiki-token-function);">write</span><span style="color:var(--shiki-token-punctuation);">(x </span><span style="color:var(--shiki-token-keyword);">+</span><span style="color:var(--shiki-token-punctuation);"> </span><span style="color:var(--shiki-token-string-expression);">'\n'</span><span style="color:var(--shiki-token-punctuation);">)</span></span>
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<span data-line> </span>
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<span data-line><span style="color:var(--shiki-token-comment);"># 特殊多行语句</span></span>
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<span data-line><span style="color:var(--shiki-color-text);">total </span><span style="color:var(--shiki-token-keyword);">=</span><span style="color:var(--shiki-color-text);"> [</span><span style="color:var(--shiki-token-string-expression);">'item_one'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'item_two'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'item_three'</span><span style="color:var(--shiki-token-punctuation);">,</span></span>
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<span data-line><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'item_four'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'item_five'</span><span style="color:var(--shiki-color-text);">]</span></span>
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<span data-line> </span>
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<span data-line><span style="color:var(--shiki-token-comment);"># 字符串</span></span>
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<span data-line><span style="color:var(--shiki-token-constant);">str</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-keyword);">=</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">"hello"</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">"world"</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">"!"</span></span></code></pre></div>
|
|||
|
|
<h2 id="复合语句">复合语句<a aria-hidden="true" tabindex="-1" href="#复合语句" class="internal"> §</a></h2>
|
|||
|
|
<p>Python 像 if、while、def 和 class 这样的复合语句，<strong>首行以关键字开始，以冒号 ( : ) 结束</strong>，该行之后的一行或多行代码构成代码组。首行及后面的代码组称为一个子句 (clause)。</p>
|
|||
|
|
<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-token-keyword);">if</span><span style="color:var(--shiki-color-text);"> expression </span><span style="color:var(--shiki-token-punctuation);">:</span><span style="color:var(--shiki-color-text);"> </span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-color-text);"> suite</span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-token-keyword);">elif</span><span style="color:var(--shiki-color-text);"> expression </span><span style="color:var(--shiki-token-punctuation);">:</span><span style="color:var(--shiki-color-text);"> </span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-color-text);"> suite </span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-token-keyword);">else</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-punctuation);">:</span><span style="color:var(--shiki-color-text);"> </span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-color-text);"> suite</span></span></code></pre></div>
|
|||
|
|
<p>此外，Python 还支持一些更高级的特性，如函数式编程、面向对象编程和元编程等。随着学习的深入，你会发现 Python 的世界越来越广阔。</p>
|
|||
|
|
<h2 id="关键字">关键字<a aria-hidden="true" tabindex="-1" href="#关键字" class="internal"> §</a></h2>
|
|||
|
|
<p>Python 的标准库提供了一个 keyword 模块，可以输出当前版本的所有关键字：</p>
|
|||
|
|
<div data-rehype-pretty-code-fragment><pre style="background-color:var(--shiki-color-background);" tabindex="0" data-language="python" data-theme="default"><code data-language="python" data-theme="default"><span data-line><span style="color:var(--shiki-color-text);">$ </span><span style="color:var(--shiki-token-keyword);">import</span><span style="color:var(--shiki-color-text);"> keyword</span></span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-color-text);">$ </span><span style="color:var(--shiki-token-function);">print</span><span style="color:var(--shiki-token-punctuation);">(keyword.kwlist)</span></span>
|
|||
|
|
<span data-line> </span>
|
|||
|
|
<span data-line><span style="color:var(--shiki-color-text);">[</span><span style="color:var(--shiki-token-string-expression);">'False'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'None'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'True'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'and'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'as'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'assert'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'async'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'await'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'break'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'class'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'continue'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'def'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'del'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'elif'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'else'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'except'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'finally'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'for'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'from'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'global'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'if'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:var(--shiki-color-text);"> </span><span style="color:var(--shiki-token-string-expression);">'import'</span><span style="color:var(--shiki-token-punctuation);">,</span><span style="color:
|
|||
|
|
<h2 id="声明">声明<a aria-hidden="true" tabindex="-1" href="#声明" class="internal"> §</a></h2>
|
|||
|
|
<p><strong>硬性规则：</strong></p>
|
|||
|
|
<ul>
|
|||
|
|
<li>变量名由<strong>字母</strong>（广义的 Unicode 字符，不包括特殊字符）、<strong>数字</strong>和<strong>下划线</strong>构成，<strong>数字不能开头</strong>。</li>
|
|||
|
|
<li><strong>大小写敏感</strong>（大写的 <code>a</code> 和小写的 <code>A</code> 是两个不同的变量）。</li>
|
|||
|
|
<li>不要跟<strong>关键字</strong>（有特殊含义的单词）和系统保留字（如函数、模块等的名字）冲突。</li>
|
|||
|
|
</ul>
|
|||
|
|
<p><strong>PEP 8 要求：</strong></p>
|
|||
|
|
<ul>
|
|||
|
|
<li>用小写字母拼写，多个单词用下划线连接。</li>
|
|||
|
|
<li>受保护的实例属性用单个下划线开头。</li>
|
|||
|
|
<li>私有的实例属性用两个下划线开头。</li>
|
|||
|
|
</ul></article></div><div class="right sidebar"><div class="graph "><h3>Graph View</h3><div class="graph-outer"><div id="graph-container" data-cfg="{"drag":true,"zoom":true,"depth":1,"scale":1.1,"repelForce":0.5,"centerForce":0.3,"linkDistance":30,"fontSize":0.6,"opacityScale":1,"showTags":true,"removeTags":[]}"></div><svg version="1.1" id="global-graph-icon" xmlns="http://www.w3.org/2000/svg" xmlnsXlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 55 55" fill="currentColor" xmlSpace="preserve"><path d="M49,0c-3.309,0-6,2.691-6,6c0,1.035,0.263,2.009,0.726,2.86l-9.829,9.829C32.542,17.634,30.846,17,29,17
|
|||
|
|
s-3.542,0.634-4.898,1.688l-7.669-7.669C16.785,10.424,17,9.74,17,9c0-2.206-1.794-4-4-4S9,6.794,9,9s1.794,4,4,4
|
|||
|
|
c0.74,0,1.424-0.215,2.019-0.567l7.669,7.669C21.634,21.458,21,23.154,21,25s0.634,3.542,1.688,4.897L10.024,42.562
|
|||
|
|
C8.958,41.595,7.549,41,6,41c-3.309,0-6,2.691-6,6s2.691,6,6,6s6-2.691,6-6c0-1.035-0.263-2.009-0.726-2.86l12.829-12.829
|
|||
|
|
c1.106,0.86,2.44,1.436,3.898,1.619v10.16c-2.833,0.478-5,2.942-5,5.91c0,3.309,2.691,6,6,6s6-2.691,6-6c0-2.967-2.167-5.431-5-5.91
|
|||
|
|
v-10.16c1.458-0.183,2.792-0.759,3.898-1.619l7.669,7.669C41.215,39.576,41,40.26,41,41c0,2.206,1.794,4,4,4s4-1.794,4-4
|
|||
|
|
s-1.794-4-4-4c-0.74,0-1.424,0.215-2.019,0.567l-7.669-7.669C36.366,28.542,37,26.846,37,25s-0.634-3.542-1.688-4.897l9.665-9.665
|
|||
|
|
C46.042,11.405,47.451,12,49,12c3.309,0,6-2.691,6-6S52.309,0,49,0z M11,9c0-1.103,0.897-2,2-2s2,0.897,2,2s-0.897,2-2,2
|
|||
|
|
S11,10.103,11,9z M6,51c-2.206,0-4-1.794-4-4s1.794-4,4-4s4,1.794,4,4S8.206,51,6,51z M33,49c0,2.206-1.794,4-4,4s-4-1.794-4-4
|
|||
|
|
s1.794-4,4-4S33,46.794,33,49z M29,31c-3.309,0-6-2.691-6-6s2.691-6,6-6s6,2.691,6,6S32.309,31,29,31z M47,41c0,1.103-0.897,2-2,2
|
|||
|
|
s-2-0.897-2-2s0.897-2,2-2S47,39.897,47,41z M49,10c-2.206,0-4-1.794-4-4s1.794-4,4-4s4,1.794,4,4S51.206,10,49,10z"></path></svg></div><div id="global-graph-outer"><div id="global-graph-container" data-cfg="{"drag":true,"zoom":true,"depth":-1,"scale":0.9,"repelForce":0.5,"centerForce":0.3,"linkDistance":30,"fontSize":0.6,"opacityScale":1,"showTags":true,"removeTags":[]}"></div></div></div><div class="toc desktop-only"><button type="button" id="toc" class><h3>Table of Contents</h3><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="fold"><polyline points="6 9 12 15 18 9"></polyline></svg></button><div id="toc-content"><ul class="overflow"><li class="depth-0"><a href="#简介" data-for="简介">简介</a></li><li class="depth-0"><a href="#使用" data-for="使用">使用</a></li><li class="depth-1"><a href="#安装" data-for="安装">安装</a></li><li class="depth-1"><a href="#运行" data-for="运行">运行</a></li><li class="depth-0"><a href="#编码" data-for="编码">编码</a></li><li class="depth-0"><a href="#注释" data-for="注释">注释</a></li><li class="depth-0"><a href="#缩进" data-for="缩进">缩进</a></li><li class="depth-0"><a href="#行语句" data-for="行语句">行语句</a></li><li class="depth-0"><a href="#复合语句" data-for="复合语句">复合语句</a></li><li class="depth-0"><a href="#关键字" data-for="关键字">关键字</a></li><li class="depth-0"><a href="#声明" data-for="声明">声明</a></li></ul></div></div><div class="backlinks "><h3>Backlinks</h3><ul class="overflow"><li>No backlinks found</li></ul></div><div class="explorer mobile-only"><button type="button" id="explorer" data-behavior="collapse" data-collapsed="collapsed" data-savestate="true" data-tree="[{"path":"Basics","collapsed":true},{"path":"Basics/english","collapsed":true},{"path":"Blog","collapsed":true},{"path":"Book","collapsed":true},{"path":"Book/个人成长","collapsed":true},{"path":"Book/医学健康","collapsed":true},{"path":"Book/历史","collapsed":true},{"path":"Book/哲学宗教","collapsed":true},{"path":"Book/心理","collapsed":true},{"path":"Book/政治军事","collapsed":true},{"path":"Book/教育学习","collapsed":true},{"path":"Book/文学","collapsed":true},{"path":"Book/生活百科","collapsed":true},{"path":"Book/社会文化","collapsed":true},{"path":"Book/科学技术","collapsed":true},{"path":"Book/经济理财","collapsed":true},{"path":"Book/艺术","collapsed":true},{"path":"Book/计算机","collapsed":true},{"path":"Company","collapsed":true},{"path":"Company/信息化","collapsed":true},{"path":"Company/信息化/规范","collapsed":true},{"path":"Culture","collapsed":true},{"path":"Government","collapsed":true},{"path":"Government/中国","collapsed":true},{"path":"Government/中国/标准","collapsed":true},{"path":"Government/中国/法律","collapsed":true},{"path":"Journal","collapsed":true},{"path":"Journal/2022","collapsed":true},{"path":"Journal/2022/W34","collapsed":true}
|
|||
|
|
function toggleCallout() {
|
|||
|
|
const outerBlock = this.parentElement;
|
|||
|
|
outerBlock.classList.toggle(`is-collapsed`);
|
|||
|
|
const collapsed = outerBlock.classList.contains(`is-collapsed`);
|
|||
|
|
const height = collapsed ? this.scrollHeight : outerBlock.scrollHeight;
|
|||
|
|
outerBlock.style.maxHeight = height + `px`;
|
|||
|
|
let current = outerBlock;
|
|||
|
|
let parent = outerBlock.parentElement;
|
|||
|
|
while (parent) {
|
|||
|
|
if (!parent.classList.contains(`callout`)) {
|
|||
|
|
return;
|
|||
|
|
}
|
|||
|
|
const collapsed2 = parent.classList.contains(`is-collapsed`);
|
|||
|
|
const height2 = collapsed2 ? parent.scrollHeight : parent.scrollHeight + current.scrollHeight;
|
|||
|
|
parent.style.maxHeight = height2 + `px`;
|
|||
|
|
current = parent;
|
|||
|
|
parent = parent.parentElement;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
function setupCallout() {
|
|||
|
|
const collapsible = document.getElementsByClassName(
|
|||
|
|
`callout is-collapsible`
|
|||
|
|
);
|
|||
|
|
for (const div of collapsible) {
|
|||
|
|
const title = div.firstElementChild;
|
|||
|
|
if (title) {
|
|||
|
|
title.removeEventListener(`click`, toggleCallout);
|
|||
|
|
title.addEventListener(`click`, toggleCallout);
|
|||
|
|
const collapsed = div.classList.contains(`is-collapsed`);
|
|||
|
|
const height = collapsed ? title.scrollHeight : div.scrollHeight;
|
|||
|
|
div.style.maxHeight = height + `px`;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
document.addEventListener(`nav`, setupCallout);
|
|||
|
|
window.addEventListener(`resize`, setupCallout);
|
|||
|
|
</script><script type="module">
|
|||
|
|
import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.esm.min.mjs';
|
|||
|
|
const darkMode = document.documentElement.getAttribute('saved-theme') === 'dark'
|
|||
|
|
mermaid.initialize({
|
|||
|
|
startOnLoad: false,
|
|||
|
|
securityLevel: 'loose',
|
|||
|
|
theme: darkMode ? 'dark' : 'default'
|
|||
|
|
});
|
|||
|
|
document.addEventListener('nav', async () => {
|
|||
|
|
await mermaid.run({
|
|||
|
|
querySelector: '.mermaid'
|
|||
|
|
})
|
|||
|
|
});
|
|||
|
|
</script><script src="https://cdn.jsdelivr.net/npm/katex@0.16.7/dist/contrib/copy-tex.min.js" type="application/javascript"></script><script src="../../../../postscript.js" type="module"></script></html>
|