zhouzhongping/wiki
1
0
Fork 0
Code
f6f2aefb5c
wiki/Technology/ProgrammingLanguage/Python/入门/控制语句.html

280 lines
511 KiB
HTML
Raw Normal View History

Deploy HTML files - 2024-10-10
2024-10-10 16:56:32 +08:00
<!DOCTYPE html>
<html lang="zh"><head><title>控制语句</title><meta charset="utf-8"/><link rel="preconnect" href="https://fonts.googleapis.com"/><link rel="preconnect" href="https://fonts.gstatic.com"/><link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=IBM Plex Mono&amp;family=Noto Serif Simplified Chinese:wght@400;700&amp;family=Source Sans Pro:ital,wght@0,400;0,600;1,400;1,600&amp;display=swap"/><meta name="viewport" content="width=device-width, initial-scale=1.0"/><meta property="og:title" content="控制语句"/><meta property="og:description" content="Python 控制语句."/><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 控制语句."/><meta name="generator" content="Quartz"/><link href="../../../../index.css" rel="stylesheet" type="text/css" spa-preserve/><link href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.16.9/katex.min.css" 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="Technology/ProgrammingLanguage/Python/入门/控制语句"><div id="quartz-root" class="page"><div id="quartz-body"><div class="left sidebar"><h2 class="page-title"><a href="../../../..">🪴 X·Eden</a></h2><div class="spacer mobile-only"></div><div class="search"><button class="search-button" id="search-button"><p>搜索</p><svg role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 19.9 19.7"><title>Search</title><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></button><div id="search-container"><div id="search-space"><input autocomplete="off" id="search-bar" name="search" type="text" aria-label="搜索些什么" placeholder="搜索些什么"/><div id="search-layout" data-preview="true"></div></div></div></div><button class="darkmode" id="darkmode"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="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" xml:space="preserve" aria-label="暗色模式"><title>暗色模式</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><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="nightIcon" x="0
<h2 id="条件语句">条件语句<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#条件语句" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h2>
<p>Python 中的条件语句是通过一条或多条语句的执行结果（即 True 或 False）来决定执行的代码块。</p>
<p>判断的值可以分为：</p>
<ul>
<li>假值 ：None、空列表、空集合、空字典，空元组、空字符串、0、False 等。</li>
<li>真值 ：非空列表、非空集合、非空字典，非空元组、非空字符串、非 0 数值、True 等。</li>
</ul>
<h3 id="if">If<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#if" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p>在 Python 中，要构造分支结构可以使用 <code>if</code>、<code>elif</code> 和 <code>else</code> 关键字。<code>elif</code> 和 <code>else</code> 都是可选的，可以根据需要进行使用。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 示例</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">>>></span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">input</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;Please enter an integer: &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">))</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">Please enter an integer: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">42</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">>>></span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'Negative changed to zero'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> elif</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'Zero'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> elif</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'Single'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'More'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<p>当然如果要构造出更多的分支，可以使用 <code>if...elif...else...</code> 结构或者嵌套的 <code>if...else...</code> 结构。</p>
<h3 id="match">Match<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#match" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p>Python 3.10 引入了新的 <code>match</code> 语句，它是模式匹配的一种形式。<code>match</code> 语句接受一个表达式并将它的值与一系列的模式进行比较。 每个模式都关联到一个代码块，当模式与表达式的值匹配时，该代码块将被执行。这在某种程度上类似于其他语言中的 switch 语句。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">def</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> http_error</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(status):</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> match</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> status:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 400</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Bad request&quot;</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 404</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Not found&quot;</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 418</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;I'm a teapot&quot;</span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> #&quot;变量名&quot; `_` 被作为 通配符 并必定会匹配成功</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> _: </span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Something's wrong with the internet&quot;</span></span></code></pre></figure>
<p>你可以使用 <code>|</code> （“ or ”）在一个模式中组合几个字面值:</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 401</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> |</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 403</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> |</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 404</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Not allowed&quot;</span></span></code></pre></figure>
<p><em>注意，<code>match</code> 语句和模式匹配的概念是 Python 3.10 中新增的特性，可能在更早版本的 Python 中无法使用。</em></p>
<h2 id="循环语句">循环语句<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#循环语句" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h2>
<h3 id="for">For<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#for" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p>Python 的 for 语句用于遍历任何序列的项目，如列表或字符串。</p>
<p>Python 的 for 语句与 C 或 Pascal 中的不同。<strong>Python 的 for 语句不迭代算术递增数值</strong>（如 Pascal），或是给予用户定义迭代步骤和暂停条件的能力（如 C），而是迭代列表或字符串等任意序列，元素的迭代顺序与在序列中出现的顺序一致。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;&quot;&quot;</span></span>
<span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">用for循环实现1~100求和</span></span>
<span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;&quot;&quot;</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">sum</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> =</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">in</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> range</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">101</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">):</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> sum</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">sum</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<p><strong>内置函数 range() 表示不可变的数字序列，通常用于在 for 循环中循环指定的次数。</strong></p>
<p>在 Python 中，<code>range()</code> 是一个内置函数，用于生成一个不可变的数字序列。通常，这个函数在 for 循环中使用，用于指定循环的次数。<code>range(101)</code> 可以用来生成一个包含 0 到 100（不包含 101）的整数序列。</p>
<p>你也可以根据需要更改 <code>range()</code> 函数的参数，例如：</p>
<ul>
<li><code>range(1, 101)</code>：生成一个包含 1 到 100（不包含 101）的整数序列。</li>
<li><code>range(1, 101, 2)</code>：生成一个包含 1 到 100 的奇数序列，其中 2 是步长。</li>
<li><code>range(100, 0, -2)</code>：生成一个包含 100 到 1 的偶数序列，其中 -2 是步长。</li>
</ul>
<h3 id="while">While<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#while" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>while</code> 循环语句用于在条件满足的情况下重复执行一个代码块。条件表达式的结果为 <code>True</code> 时，继续循环；结果为 <code>False</code> 时，结束循环。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;&quot;&quot;</span></span>
<span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">猜数字游戏</span></span>
<span data-line><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;&quot;&quot;</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">import</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> random</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">answer </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> random.randint(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">counter </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> True</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> counter </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> number </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">input</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'请输入: '</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">))</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> number </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> answer:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'大一点'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> elif</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> number </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">></span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> answer:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'小一点'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'恭喜你猜对了!'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'你总共猜了</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">次'</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> counter)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> counter </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">></span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'你的智商余额明显不足'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<h3 id="break">Break<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#break" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>break</code> 语句可以提前退出循环。具体来说，<strong><code>break</code> 用于完全结束一个循环，并跳出该循环体。</strong></p>
<h3 id="continue">Continue<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#continue" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>continue</code> 语句用于<strong>跳过当前循环的剩余语句，然后继续进行下一轮循环。</strong></p>
<h3 id="else">Else<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#else" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p>在 Python 中，<code>else</code> 子句可以与 <code>for</code> 循环和 <code>while</code> 循环一起使用。当循环正常完成（即没有碰到 <code>break</code> 语句）时，<code>else</code> 块的内容会被执行。这个特性在很多其他语言中都没有，因此对于初学者来说可能会感到有些不熟悉。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 使用 else 的 for 循环的示例</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">in</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> range</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">):</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;循环正常完成&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<p>在这个示例中，循环会正常完成，因为没有任何一个元素使得 <code>i == 10</code> 为 <code>True</code>，所以 <code>break</code> 语句不会被执行，<code>else</code> 块的内容会被打印出来。</p>
<p>如果我们修改 <code>if</code> 语句的条件使得 <code>break</code> 语句被执行，那么 <code>else</code> 块的内容就不会被打印出来：</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="Python" data-theme="github-light github-dark"><code data-language="Python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span>for i in range(5):</span></span>
<span data-line><span> if i == 3:</span></span>
<span data-line><span> break</span></span>
<span data-line><span>else:</span></span>
<span data-line><span> print(&quot;循环正常完成&quot;)</span></span></code></pre></figure>
<p>在这个示例中，当 <code>i</code> 等于 3 时，<code>break</code> 语句就会被执行，所以循环没有正常完成，<code>else</code> 块的内容不会被打印出来。</p>
<p>同样的，<code>else</code> 也可以与 <code>while</code> 循环一起使用，当 <code>while</code> 循环的条件变为 <code>False</code> 时，<code>else</code> 块的内容会被执行。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;循环正常完成&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<p>在这个示例中，当 <code>i</code> 等于 3 时，<code>break</code> 语句就会被执行，所以循环没有正常完成，<code>else</code> 块的内容不会被打印出来。</p>
<h2 id="异常语句">异常语句<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#异常语句" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h2>
<h3 id="tryexceptfinally">try、except、finally<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#tryexceptfinally" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<pre><code class="mermaid">graph TD
A(开始)
B[try 块]
C[except 块1]
D[except 块2]
E[else 块]
F[finally 块]
G(结束)
A --> B
B -- 异常1 --> C
B -- 异常2 --> D
B -- 无异常 --> E
C --> F
D --> F
E --> F
F --> G
</code></pre>
<ol>
<li><strong>确定需要的异常处理结构</strong>：在开始编写异常处理结构时，首先确定你需要 <code>try</code>, <code>except</code>, <code>else</code> 和/或 <code>finally</code> 语句块。要记住的是，<code>except</code> 和 <code>finally</code> 块至少需要一个，否则 <code>try</code> 将失去其意义。</li>
<li><strong>编写 <code>try</code> 语句块</strong>：将可能抛出异常的代码放入 <code>try</code> 块。如果在 <code>try</code> 块中发生异常，Python 将停止执行 <code>try</code> 块的其余部分，并转到 <code>except</code> 块。</li>
<li><strong>编写 <code>except</code> 语句块</strong>：为每种可能抛出的异常类型编写一个 <code>except</code> 块。Python 会按照它们在代码中出现的顺序来检查这些 <code>except</code> 块。如果匹配到异常，Python 将执行相应的 <code>except</code> 块并停止查找。</li>
<li><strong>处理多个异常</strong>：你可以将多个异常类型放入一个元组中，然后使用一个 <code>except</code> 块来处理它们。例如：<code>except (TypeError, ValueError):</code>。</li>
<li><strong>处理所有异常</strong>：如果 <code>except</code> 块后面没有指定异常类型，那么这个 <code>except</code> 块将处理所有异常。你可以通过 <code>logging</code> 或 <code>sys</code> 模块获取异常的详细信息。</li>
<li><strong>重新抛出异常</strong>：如果你在 <code>except</code> 块中捕获了一个异常，然后想要再次抛出它，你可以使用 <code>raise</code> 语句而不需要附加任何参数或信息。</li>
<li><strong>编写 <code>else</code> 语句块</strong>：<code>else</code> 块中的代码只有在 <code>try</code> 块没有发生任何异常时才会被执行。</li>
<li><strong>编写 <code>finally</code> 语句块</strong>：无论是否发生异常，<code>finally</code> 块中的代码总是会被执行。这对于清理（例如关闭文件或网络连接）非常有用。</li>
<li><strong>重构代码</strong>：考虑使用 <code>with</code> 语句或 <code>getattr()</code> 方法等内置的异常处理语句，而不是 <code>try/except</code>。此外，如果可能，尽量避免在同一个 <code>except</code> 块中捕获和抛出相同的异常。最后，除非你确定需要处理所有可能的异常，否则不应该捕获所有异常，因为这可能会隐藏严重的问题。</li>
</ol>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 示例</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 这里可能会抛出异常的代码</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> do_something()</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">except</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> SomeException </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">as</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e:</span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 当捕获到SomeException时的处理代码</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handle_exception(e)</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 实例</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">def</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> div</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a, b):</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> except</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> ZeroDivisionError</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;错误：b 不应为 0 !!&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> except</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> Exception</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> as</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;意外错误：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">{}</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.format(e))</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'只有当一切正常时，才会运行 else'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> finally</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'始终运行 finally 块。'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 测试</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">div(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">div(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'错误的类型'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">div(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line> </span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 在一行中捕获多个异常</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">except</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">ZeroDivisionError</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">TypeError</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">as</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(e)</span></span>
<span data-line> </span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 当存在 finally 时，except 是可选的</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> open</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(database)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">finally</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> close(database)</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 捕获所有错误并记录下来</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> do_work()</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">except</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">: </span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 从 logging 模块获取详细信息</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> logging.exception(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'捕获到异常!'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> </span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 从 sys.exc_info() 方法获取详细信息</span></span>
<span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> error_type, error_value, trace_back </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sys.exc_info()</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(error_value)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> raise</span></span></code></pre></figure>
<h3 id="with">With<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#with" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p>Python 的 with 语句支持通过上下文管理器所定义的运行时上下文这一概念。</p>
<p><code>with</code> 语句是一种处理上下文管理器的语句，上下文管理器通常包含 <code>__enter__</code> 和 <code>__exit__</code> 这两个方法。在 <code>with</code> 语句的代码块被执行前，会首先执行 <code>__enter__</code> 方法，在执行完毕后，会调用 <code>__exit__</code> 方法。这在你需要管理资源，如文件，网络连接或锁定等情况非常有用，因为它可以<strong>保证在任何情况下都会执行必要的清理操作。</strong></p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 在这里，文件已经被关闭，无需再次手动关闭</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">with</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> open</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;file.txt&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;r&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">as</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> file</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> line </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">in</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> file</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(line)</span></span></code></pre></figure>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 基本思想是 with 所求值的对象必须有一个 enter() 方法，一个 exit() 方法。</span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 紧跟 with 后面的语句被求值后，返回对象的 enter() 方法被调用，并将返回值赋值给 as 后面的变量。</span></span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 当 with 的代码块全部被执行完之后，将调用前面返回对象的 exit() 方法。</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> ManagedFile</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> def</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> __init__</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(self, filename):</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.filename </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> filename</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> def</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> __enter__</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(self):</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.file </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> open</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.filename, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'r'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.file</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> def</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> __exit__</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(self, exc_type, exc_val, exc_tb):</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.file:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> self</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.file.close()</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 使用自定义的上下文管理器</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">with</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ManagedFile(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;file.txt&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">as</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> file</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">file</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">.read())</span></span></code></pre></figure>
<h3 id="raise">Raise<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#raise" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>raise</code> 语句用于引发特定的异常。你可以定义异常类型并附加一个错误消息：</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">raise</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> ValueError</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;这是一个无效的值！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span></code></pre></figure>
<p>如果你在 <code>except</code> 块中使用 <code>raise</code> 语句，而不提供任何参数，它将默认重新引发最近的异常。</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">try</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">5</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">except</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> ZeroDivisionError</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> as</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e:</span></span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;发生了一个错误！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> raise</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 重新引发最近的异常</span></span></code></pre></figure>
<h2 id="其他语句">其他语句<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#其他语句" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h2>
<h3 id="assert">Assert<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#assert" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>assert</code> 语句用于断言某个条件为真，如果条件为假，则会抛出 <code>AssertionError</code> 异常。它常常用于调试代码，确认代码的某些方面满足预期，例如：</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">assert</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 条件为真，没有问题</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 条件为假，抛出 AssertionError，并附带错误信息</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">assert</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x should be 2 but is actually &quot;</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> str</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(x) </span></span></code></pre></figure>
<p><em>注意，<code>assert</code> 语句在优化模式下（使用 <code>-O</code> 参数启动 Python 时）会被全局禁用。</em></p>
<h3 id="pass">Pass<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#pass" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>pass</code> 语句是 Python 中的空语句，用于在需要语句的地方保持语法的完整性，但是<strong>实际上不做任何事情</strong>。通常，我们使用它作为未完成代码的占位符：</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">def</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> my_function</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">():</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> pass</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">TODO</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">: implement this function</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> MyEmptyClass</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> pass</span></span></code></pre></figure>
<h3 id="return">Return<a role="anchor" aria-hidden="true" tabindex="-1" data-no-popover="true" href="#return" class="internal"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></a></h3>
<p><code>return</code> 语句用于从函数返回一个值。所有函数都会返回一个值：如果函数执行到结尾而没有遇到 <code>return</code> 语句，它将返回特殊值 <code>None</code>：</p>
<figure data-rehype-pretty-code-figure><pre tabindex="0" data-language="python" data-theme="github-light github-dark"><code data-language="python" data-theme="github-light github-dark" style="display:grid;"><span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">def</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> add</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a, b):</span></span>
<span data-line><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b</span></span>
<span data-line> </span>
<span data-line><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">print</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(add(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)) </span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"># 输出：3</span></span></code></pre></figure></article><hr/><div class="page-footer"></div></div><div class="right sidebar"><div class="graph"><h3>关系图谱</h3><div class="graph-outer"><div id="graph-container" data-cfg="{&quot;drag&quot;:true,&quot;zoom&quot;:true,&quot;depth&quot;:1,&quot;scale&quot;:1.1,&quot;repelForce&quot;:0.5,&quot;centerForce&quot;:0.3,&quot;linkDistance&quot;:30,&quot;fontSize&quot;:0.6,&quot;opacityScale&quot;:1,&quot;showTags&quot;:true,&quot;removeTags&quot;:[],&quot;focusOnHover&quot;:false}"></div><button id="global-graph-icon" aria-label="Global Graph"><svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 55 55" fill="currentColor" xml:space="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></button></div><div id="global-graph-outer"><div id="global-graph-container" data-cfg="{&quot;drag&quot;:true,&quot;zoom&quot;:true,&quot;depth&quot;:-1,&quot;scale&quot;:0.9,&quot;repelForce&quot;:0.5,&quot;centerForce&quot;:0.3,&quot;linkDistance&quot;:30,&quot;fontSize&quot;:0.6,&quot;opacityScale&quot;:1,&quot;showTags&quot;:true,&quot;removeTags&quot;:[],&quot;focusOnHover&quot;:true}"></div></div></div><div class="toc desktop-only"><button type="button" id="toc" class aria-controls="toc-content" aria-expanded="true"><h3>目录</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" class><ul class="overflow"><li class="depth-0"><a href="#条件语句" data-for="条件语句">条件语句</a></li><li class="depth-1"><a href="#if" data-for="if">If</a></li><li class="depth-1"><a href="#match" data-for="match">Match</a></li><li class="depth-0"><a href="#循环语句" data-for="循环语句">循环语句</a></li><li class="depth-1"><a href="#for" data-for="for">For</a></li><li class="depth-1"><a href="#while" data-for="while">While</a></li><li class="depth-1"><a href="#break" data-for="break">Break</a></li><li class="depth-1"><a href="#continue" data-for="continue">Continue</a></li><li class="depth-1"><a href="#else" data-for="else">Else</a></li><li class="depth-0"><a href="#异常语句" data-for="异常语句">异常语句</a></li><li class="depth-1"><a href="#tryexceptfinally" data-for="tryexceptfinally">try、except、finally</a></li><li class="depth-1"><a href="#with" data-for="with">With</a></li><li class="depth-1"><a href="#raise" data-for="raise">Raise</a></li><li class="depth-0"><a href="#其他语句" data-for="其他语句">其他语句</a></li><li class="depth-1"><a href="#assert" data-for="assert">Assert</a></li><li class="depth-1"><a href="#pass" data-for="pass">Pass</a></li><li class="depth-1"><a href="#return" data-for="return">Return</a></li></ul></div></div><div class="explorer mobile-only"><button type="button" id="explorer" data-behavior="collapse" data-collapsed="collapsed" data-savestate="true" data-tree="[{&quot;path&quot;:&quot;Personal&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2018&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2020&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2021&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2022&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2023&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Blog/2024&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/个人成长&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/医学健康&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/历史&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/哲学宗教&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/心理&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/政治军事&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/教育学习&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/文学&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/生活百科&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/社会文化&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/科学技术&quot;,&quot;collapsed&quot;:true},{&quot;path&quot;:&quot;Personal/Book/经济理财&quot;,&quot;collapsed&q
</script><script type="module">
let mermaidImport = undefined
document.addEventListener('nav', async () => {
if (document.querySelector("code.mermaid")) {
mermaidImport ||= await import('https://cdnjs.cloudflare.com/ajax/libs/mermaid/10.7.0/mermaid.esm.min.mjs')
const mermaid = mermaidImport.default
const darkMode = document.documentElement.getAttribute('saved-theme') === 'dark'
mermaid.initialize({
startOnLoad: false,
securityLevel: 'loose',
theme: darkMode ? 'dark' : 'default'
})
await mermaid.run({
querySelector: '.mermaid'
})
}
});
</script><script src="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.16.9/contrib/copy-tex.min.js" type="application/javascript"></script><script src="../../../../postscript.js" type="module"></script></html>
Copy Permalink