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<a aria-hidden="true" tabindex="-1" href="#lua-备忘清单"><span class="icon icon-link"></span></a>Lua 备忘清单</h1><div class="wrap-body">
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<p>包含最重要概念、函数、方法等的 Lua 备忘单。 初学者的完整快速参考。</p>
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</div></header><div class="menu-tocs"><div class="menu-btn"><svg aria-hidden="true" fill="currentColor" height="1em" width="1em" viewBox="0 0 16 16" version="1.1" data-view-component="true">
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<path fill-rule="evenodd" d="M2 4a1 1 0 100-2 1 1 0 000 2zm3.75-1.5a.75.75 0 000 1.5h8.5a.75.75 0 000-1.5h-8.5zm0 5a.75.75 0 000 1.5h8.5a.75.75 0 000-1.5h-8.5zm0 5a.75.75 0 000 1.5h8.5a.75.75 0 000-1.5h-8.5zM3 8a1 1 0 11-2 0 1 1 0 012 0zm-1 6a1 1 0 100-2 1 1 0 000 2z"></path>
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</svg></div><div class="menu-modal"><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#入门">入门</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#下载">下载</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#其它下载方式">其它下载方式</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#hello-world">hello world</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#运行">运行</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#注释">注释</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#单行注释">单行注释</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#多行注释">多行注释</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#type-函数">type() 函数</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#number">number</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#string">string</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#">[[]]</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#字符串连接">字符串连接(..)</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#字符串长度">字符串长度(#)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#table">table</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#迭代-table">迭代 table</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#指定键">指定键</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#变量">变量</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#默认值">默认值</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#全局和局部变量">全局和局部变量</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#赋值">赋值</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#交换变量">交换变量</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#赋值个数不一致">赋值个数不一致</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#运算符">运算符</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#类型转换">类型转换</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#条件语句">条件语句</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#运算符-1">运算符</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#关系运算符">关系运算符</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#逻辑运算符">逻辑运算符</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#while-循环">while 循环</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#if-语句">if 语句</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#if--elseif--else">if .. elseif() .. else</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#for-循环">for 循环</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#repeatuntil-循环">repeat...until 循环</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#break">break</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#另见">另见</a></div></div><div class="h1wrap-body"><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="入门"><a aria-hidden="true" tabindex="-1" href="#入门"><span class="icon icon-link"></span></a>入门</h2><div class="wrap-body">
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</div></div><div class="h2wrap-body"><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="下载"><a aria-hidden="true" tabindex="-1" href="#下载"><span class="icon icon-link"></span></a>下载</h3><div class="wrap-body">
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<p>macos 使用 homebrew 下载</p>
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<pre class="language-bash"><code class="language-bash code-highlight"><span class="code-line">$ brew <span class="token function">install</span> lua
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</span></code></pre>
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<h4 id="其它下载方式"><a aria-hidden="true" tabindex="-1" href="#其它下载方式"><span class="icon icon-link"></span></a>其它下载方式</h4>
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<ul>
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<li><a href="https://luabinaries.sourceforge.net/download.html">下载地址</a></li>
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</ul>
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<pre class="language-bash"><code class="language-bash code-highlight"><span class="code-line"><span class="token comment"># 查看 lua 是否安装成功</span>
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</span><span class="code-line">$ lua <span class="token parameter variable">-v</span>
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</span></code></pre>
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</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="hello-world"><a aria-hidden="true" tabindex="-1" href="#hello-world"><span class="icon icon-link"></span></a>hello world</h3><div class="wrap-body">
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<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">#!/usr/bin/env lua</span>
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</span><span class="code-line">
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</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"Hello World!"</span><span class="token punctuation">)</span>
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</span></code></pre>
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<h4 id="运行"><a aria-hidden="true" tabindex="-1" href="#运行"><span class="icon icon-link"></span></a>运行</h4>
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<pre class="language-bash"><code class="language-bash code-highlight"><span class="code-line">$ lua ./hello.lua
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</span><span class="code-line"><span class="token comment"># 或者也可以像 bash 脚本一样</span>
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</span><span class="code-line">$ <span class="token function">chmod</span> +x hello.lua
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</span><span class="code-line">./hello.lua
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</span></code></pre>
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</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="注释"><a aria-hidden="true" tabindex="-1" href="#注释"><span class="icon icon-link"></span></a>注释</h3><div class="wrap-body">
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<h4 id="单行注释"><a aria-hidden="true" tabindex="-1" href="#单行注释"><span class="icon icon-link"></span></a>单行注释</h4>
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<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">-- 以两个减号开始</span>
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</span></code></pre>
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<h4 id="多行注释"><a aria-hidden="true" tabindex="-1" href="#多行注释"><span class="icon icon-link"></span></a>多行注释</h4>
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<p>多行注释以 <code>--[[</code> 开头, 以 <code>]]</code> 结尾</p>
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<pre class="wrap-text "><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">--[[
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</span></span><span class="code-line"><span class="token comment">
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</span></span><span class="code-line"><span class="token comment">]]</span>
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</span></code></pre>
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<!--rehype:className=wrap-text -->
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</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="type-函数"><a aria-hidden="true" tabindex="-1" href="#type-函数"><span class="icon icon-link"></span></a>type() 函数</h3><div class="wrap-body">
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<p>使用 <code>type()</code> 函数可以判断变量或者值的类型</p>
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<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token function">type</span><span class="token punctuation">(</span><span class="token keyword">true</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">-- boolean</span>
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</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token function">type</span><span class="token punctuation">(</span><span class="token keyword">nil</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">-- nil</span>
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</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="number"><a aria-hidden="true" tabindex="-1" href="#number"><span class="icon icon-link"></span></a>number</h3><div class="wrap-body">
|
||
<p>Lua 默认只有一种 number 类型 double (双精度) 类型</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token number">0.3</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>2e <span class="token operator">+</span> <span class="token number">10</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="string"><a aria-hidden="true" tabindex="-1" href="#string"><span class="icon icon-link"></span></a>string</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">-- 使用 ''</span>
|
||
</span><span class="code-line"><span class="token keyword">local</span> str1 <span class="token operator">=</span> <span class="token string">'str1'</span>
|
||
</span><span class="code-line"><span class="token comment">-- 使用 ""</span>
|
||
</span><span class="code-line"><span class="token keyword">local</span> str2 <span class="token operator">=</span> <span class="token string">"str2"</span>
|
||
</span></code></pre>
|
||
<h4 id=""><a aria-hidden="true" tabindex="-1" href="#"><span class="icon icon-link"></span></a><code>[[]]</code></h4>
|
||
<p>使用 <code>[[]]</code> 跨行表示多个字符串</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> html <span class="token operator">=</span> <span class="token string">[[
|
||
</span></span><span class="code-line"><span class="token string"><html>
|
||
</span></span><span class="code-line"><span class="token string"><head></head>
|
||
</span></span><span class="code-line"><span class="token string"><body>
|
||
</span></span><span class="code-line"><span class="token string"> <a href="https://www.twle.cn/">简单编程</a>
|
||
</span></span><span class="code-line"><span class="token string"></body>
|
||
</span></span><span class="code-line"><span class="token string"></html>
|
||
</span></span><span class="code-line"><span class="token string">]]</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>html<span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<h4 id="字符串连接"><a aria-hidden="true" tabindex="-1" href="#字符串连接"><span class="icon icon-link"></span></a>字符串连接(<code>..</code>)</h4>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"a"</span> <span class="token operator">..</span> <span class="token string">'b'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">-- ab</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token number">157</span> <span class="token operator">..</span> <span class="token number">428</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">-- 157428</span>
|
||
</span></code></pre>
|
||
<h4 id="字符串长度"><a aria-hidden="true" tabindex="-1" href="#字符串长度"><span class="icon icon-link"></span></a>字符串长度(<code>#</code>)</h4>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token operator">#</span><span class="token string">"string"</span><span class="token punctuation">)</span> <span class="token comment">-- 6</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="table"><a aria-hidden="true" tabindex="-1" href="#table"><span class="icon icon-link"></span></a>table</h3><div class="wrap-body">
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> table <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
|
||
</span></code></pre>
|
||
<h4 id="迭代-table"><a aria-hidden="true" tabindex="-1" href="#迭代-table"><span class="icon icon-link"></span></a>迭代 table</h4>
|
||
<p>默认的初始索引会从 1 开始</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> array <span class="token operator">=</span> <span class="token punctuation">{</span> <span class="token string">"apple"</span><span class="token punctuation">,</span> <span class="token string">"pear"</span><span class="token punctuation">,</span> <span class="token string">"orange"</span><span class="token punctuation">,</span> <span class="token string">"grape"</span> <span class="token punctuation">}</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>array<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">-- apple</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token keyword">for</span> k<span class="token punctuation">,</span> v <span class="token keyword">in</span> <span class="token function">pairs</span><span class="token punctuation">(</span>array<span class="token punctuation">)</span> <span class="token keyword">do</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span>k <span class="token operator">..</span> <span class="token string">" : "</span> <span class="token operator">..</span> v<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span><span class="code-line"><span class="token comment">-- 1 : apple</span>
|
||
</span><span class="code-line"><span class="token comment">-- 2 : pear</span>
|
||
</span><span class="code-line"><span class="token comment">-- 3 : orange</span>
|
||
</span><span class="code-line"><span class="token comment">-- 4 : grape</span>
|
||
</span></code></pre>
|
||
<h4 id="指定键"><a aria-hidden="true" tabindex="-1" href="#指定键"><span class="icon icon-link"></span></a>指定键</h4>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> array <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
|
||
</span><span class="code-line">array<span class="token punctuation">.</span>one <span class="token operator">=</span> <span class="token string">"apple"</span>
|
||
</span><span class="code-line">array<span class="token punctuation">[</span><span class="token string">"two"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"peach"</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>array<span class="token punctuation">.</span>one<span class="token punctuation">)</span> <span class="token comment">-- apple</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>array<span class="token punctuation">.</span>two<span class="token punctuation">)</span> <span class="token comment">-- peach</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="变量"><a aria-hidden="true" tabindex="-1" href="#变量"><span class="icon icon-link"></span></a>变量</h3><div class="wrap-body">
|
||
<h4 id="默认值"><a aria-hidden="true" tabindex="-1" href="#默认值"><span class="icon icon-link"></span></a>默认值</h4>
|
||
<p>变量的默认值均是 nil</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">#!/usr/bin/env lua</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span> <span class="token comment">-- nil</span>
|
||
</span></code></pre>
|
||
<h4 id="全局和局部变量"><a aria-hidden="true" tabindex="-1" href="#全局和局部变量"><span class="icon icon-link"></span></a>全局和局部变量</h4>
|
||
<p>Lua 中的变量全是全局变量，那怕是语句块或是函数里，除非用 local 显式声明为局部变量</p>
|
||
<pre class="wrap-text "><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">#!/usr/bin/env lua</span>
|
||
</span><span class="code-line"><span class="token keyword">function</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token keyword">local</span> b <span class="token operator">=</span> <span class="token number">12</span>
|
||
</span><span class="code-line"> a <span class="token operator">=</span> <span class="token number">23</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span> <span class="token comment">-- 23</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span> <span class="token comment">-- nil</span>
|
||
</span></code></pre>
|
||
<!--rehype:className=wrap-text -->
|
||
</div></div></div><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="赋值"><a aria-hidden="true" tabindex="-1" href="#赋值"><span class="icon icon-link"></span></a>赋值</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line">a <span class="token operator">=</span> <span class="token string">"hello "</span> <span class="token operator">..</span> <span class="token string">"world"</span> <span class="token comment">-- 改变 变量</span>
|
||
</span><span class="code-line">t<span class="token punctuation">.</span>n <span class="token operator">=</span> t<span class="token punctuation">.</span>n <span class="token operator">+</span> <span class="token number">1</span> <span class="token comment">-- 改变 table</span>
|
||
</span></code></pre>
|
||
<hr>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token comment">-- 给多个变量赋值</span>
|
||
</span><span class="code-line">a<span class="token punctuation">,</span> b <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token operator">*</span>a <span class="token comment">--> a=10; b=20</span>
|
||
</span></code></pre>
|
||
<h4 id="交换变量"><a aria-hidden="true" tabindex="-1" href="#交换变量"><span class="icon icon-link"></span></a>交换变量</h4>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> x<span class="token punctuation">,</span> y <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">3</span>
|
||
</span><span class="code-line">x<span class="token punctuation">,</span> y <span class="token operator">=</span> y<span class="token punctuation">,</span> x
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>x<span class="token punctuation">,</span> y<span class="token punctuation">)</span> <span class="token comment">-- 3, 1</span>
|
||
</span></code></pre>
|
||
<hr>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> tab <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
|
||
</span><span class="code-line">tab<span class="token punctuation">.</span>one <span class="token operator">=</span> <span class="token number">2</span>
|
||
</span><span class="code-line">tab<span class="token punctuation">.</span>two <span class="token operator">=</span> <span class="token number">1</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line">tab<span class="token punctuation">[</span><span class="token string">"one"</span><span class="token punctuation">]</span><span class="token punctuation">,</span> tab<span class="token punctuation">[</span><span class="token string">"two"</span><span class="token punctuation">]</span> <span class="token operator">=</span> tab<span class="token punctuation">.</span>two<span class="token punctuation">,</span> tab<span class="token punctuation">.</span>one
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>tab<span class="token punctuation">.</span>one<span class="token punctuation">,</span> tab<span class="token punctuation">.</span>two<span class="token punctuation">)</span> <span class="token comment">-- 1 2</span>
|
||
</span></code></pre>
|
||
<h4 id="赋值个数不一致"><a aria-hidden="true" tabindex="-1" href="#赋值个数不一致"><span class="icon icon-link"></span></a>赋值个数不一致</h4>
|
||
<ul class="style-round">
|
||
<li>
|
||
<p>如果变量个数<strong>大于</strong>值的个数，按变量个数补足 nil</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line">a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">3</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token comment">--> 1 3 nil</span>
|
||
</span></code></pre>
|
||
</li>
|
||
<li>
|
||
<p>如果变量个数<strong>小于</strong>值的个数，多余的值会被忽略</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line">a <span class="token operator">=</span> <span class="token number">1</span>
|
||
</span><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b <span class="token operator">=</span> a<span class="token punctuation">,</span> a <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">,</span> a <span class="token operator">+</span> <span class="token number">2</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span> <span class="token comment">--> 1 2</span>
|
||
</span></code></pre>
|
||
</li>
|
||
</ul>
|
||
<!--rehype:className=style-round-->
|
||
<!--rehype:className=wrap-text -->
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="运算符"><a aria-hidden="true" tabindex="-1" href="#运算符"><span class="icon icon-link"></span></a>运算符</h3><div class="wrap-body">
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<table><thead><tr><th align="left">:-</th><th align="left">:-</th></tr></thead><tbody><tr><td align="left">+</td><td align="left">加法</td></tr><tr><td align="left">-</td><td align="left">减法</td></tr><tr><td align="left">*</td><td align="left">乘法</td></tr><tr><td align="left">/</td><td align="left">除法</td></tr><tr><td align="left">%</td><td align="left">取余，求出除法的余数</td></tr><tr><td align="left">^</td><td align="left">乘幂，计算次方</td></tr><tr><td align="left">-</td><td align="left">负号，取负值</td></tr></tbody></table>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b <span class="token operator">=</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">3</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">+</span> b<span class="token punctuation">)</span> <span class="token comment">-- 7</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">-</span> b<span class="token punctuation">)</span> <span class="token comment">-- 1</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">/</span> b<span class="token punctuation">)</span> <span class="token comment">-- 1.3333333333333</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">*</span> b<span class="token punctuation">)</span> <span class="token comment">-- 12</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">%</span> b<span class="token punctuation">)</span> <span class="token comment">-- 1</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">^</span> b<span class="token punctuation">)</span> <span class="token comment">-- 64.0</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="类型转换"><a aria-hidden="true" tabindex="-1" href="#类型转换"><span class="icon icon-link"></span></a>类型转换</h3><div class="wrap-body">
|
||
<ul class="style-round">
|
||
<li>
|
||
<p>在算术运算中，string 类型会尝试自动转换为 number 时</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c <span class="token operator">=</span> <span class="token string">"str"</span><span class="token punctuation">,</span> <span class="token string">"1"</span><span class="token punctuation">,</span> <span class="token string">"2"</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">-- print(a + b) -- error</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>b <span class="token operator">+</span> c<span class="token punctuation">)</span> <span class="token comment">-- 3</span>
|
||
</span></code></pre>
|
||
</li>
|
||
<li>
|
||
<p>number 类型使用 <code>..</code> 会自动转换为 string</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token function">type</span><span class="token punctuation">(</span>a <span class="token operator">..</span> b<span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</li>
|
||
<li>
|
||
<p>其它方式的转换</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token function">type</span><span class="token punctuation">(</span><span class="token function">tostring</span><span class="token punctuation">(</span><span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">-- string</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token function">type</span><span class="token punctuation">(</span><span class="token function">tonumber</span><span class="token punctuation">(</span><span class="token string">"12"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">-- number</span>
|
||
</span></code></pre>
|
||
</li>
|
||
</ul>
|
||
<!--rehype:className=style-round-->
|
||
<!--rehype:className=wrap-text -->
|
||
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="条件语句"><a aria-hidden="true" tabindex="-1" href="#条件语句"><span class="icon icon-link"></span></a>条件语句</h2><div class="wrap-body">
|
||
</div></div><div class="h2wrap-body"><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="运算符-1"><a aria-hidden="true" tabindex="-1" href="#运算符-1"><span class="icon icon-link"></span></a>运算符</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<h4 id="关系运算符"><a aria-hidden="true" tabindex="-1" href="#关系运算符"><span class="icon icon-link"></span></a>关系运算符</h4>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<table class="show-header"><thead><tr><th align="left">符号</th><th align="left">含义</th></tr></thead><tbody><tr><td align="left">==</td><td align="left">等于</td></tr><tr><td align="left">~=</td><td align="left">不等于</td></tr><tr><td align="left">></td><td align="left">大于</td></tr><tr><td align="left"><</td><td align="left">小于</td></tr><tr><td align="left">>=</td><td align="left">大于等于</td></tr><tr><td align="left"><=</td><td align="left">小于等于</td></tr></tbody></table>
|
||
<!--rehype:className=show-header-->
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b <span class="token operator">=</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">3</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator"><</span> b<span class="token punctuation">)</span> <span class="token comment">-- false</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator"><=</span> b<span class="token punctuation">)</span> <span class="token comment">-- false</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">==</span> b<span class="token punctuation">)</span> <span class="token comment">-- false</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">~=</span> b<span class="token punctuation">)</span> <span class="token comment">-- true</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">></span> b<span class="token punctuation">)</span> <span class="token comment">-- true</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token operator">>=</span> b<span class="token punctuation">)</span><span class="token comment">-- true</span>
|
||
</span></code></pre>
|
||
<h4 id="逻辑运算符"><a aria-hidden="true" tabindex="-1" href="#逻辑运算符"><span class="icon icon-link"></span></a>逻辑运算符</h4>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<table class="show-header"><thead><tr><th align="left">符号</th><th align="left">含义</th></tr></thead><tbody><tr><td align="left"><code>and</code></td><td align="left">逻辑与</td></tr><tr><td align="left"><code>or</code></td><td align="left">逻辑或操作符</td></tr><tr><td align="left"><code>not</code></td><td align="left">逻辑非操作符</td></tr></tbody></table>
|
||
<!--rehype:className=show-header-->
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> a<span class="token punctuation">,</span> b <span class="token operator">=</span> <span class="token keyword">true</span><span class="token punctuation">,</span> <span class="token keyword">false</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token keyword">and</span> b<span class="token punctuation">)</span> <span class="token comment">-- false</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token keyword">and</span> <span class="token keyword">not</span> b<span class="token punctuation">)</span> <span class="token comment">-- true</span>
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span>a <span class="token keyword">or</span> b<span class="token punctuation">)</span> <span class="token comment">-- true</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="while-循环"><a aria-hidden="true" tabindex="-1" href="#while-循环"><span class="icon icon-link"></span></a>while 循环</h3><div class="wrap-body">
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> num <span class="token operator">=</span> <span class="token number">1</span>
|
||
</span><span class="code-line"><span class="token keyword">while</span> <span class="token punctuation">(</span>num <span class="token operator"><</span> <span class="token number">5</span><span class="token punctuation">)</span> <span class="token keyword">do</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"num 的值为:"</span><span class="token punctuation">,</span> num<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> num <span class="token operator">=</span> num <span class="token operator">+</span> <span class="token number">1</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="if-语句"><a aria-hidden="true" tabindex="-1" href="#if-语句"><span class="icon icon-link"></span></a>if 语句</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<p><span style="color:red">注意: Lua 中 0 为 true，但是 Lua 中的 <code>nil</code> 可以当作 <code>false</code></span></p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">if</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">then</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"0 为 true"</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span></code></pre>
|
||
<h4 id="if--elseif--else"><a aria-hidden="true" tabindex="-1" href="#if--elseif--else"><span class="icon icon-link"></span></a>if .. elseif() .. else</h4>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> age <span class="token operator">=</span> <span class="token number">27</span><span class="token punctuation">;</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token keyword">if</span> <span class="token punctuation">(</span>age <span class="token operator"><</span> <span class="token number">18</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">then</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"age 小于 18"</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">elseif</span> <span class="token punctuation">(</span>age <span class="token operator"><</span> <span class="token number">25</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">then</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"age 小于 25"</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">elseif</span> <span class="token punctuation">(</span>age <span class="token operator"><</span> <span class="token number">30</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">then</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"age 小于 30"</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">else</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"age 大于 30"</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"age 的值为 :"</span><span class="token punctuation">,</span> age<span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="for-循环"><a aria-hidden="true" tabindex="-1" href="#for-循环"><span class="icon icon-link"></span></a>for 循环</h3><div class="wrap-body">
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token operator">-</span><span class="token number">1</span> <span class="token keyword">do</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span></code></pre>
|
||
<ul class="style-round">
|
||
<li>
|
||
<p>lua 中的 for 循环从参数 1 变化到参数 2，每次变化以参数 3 为步长递增 i，并执行一次表达式</p>
|
||
</li>
|
||
<li>
|
||
<p>参数三，是可选的，如果不指定，默认是 1</p>
|
||
</li>
|
||
<li>
|
||
<p>参数二只会在一开始求值，其后不会再进行运算</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> f <span class="token operator">=</span> <span class="token keyword">function</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"in f(x) "</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token keyword">return</span> x <span class="token operator">*</span> <span class="token number">2</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token function">f</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span> <span class="token keyword">do</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">end</span>
|
||
</span></code></pre>
|
||
</li>
|
||
</ul>
|
||
<!--rehype:className=style-round-->
|
||
<!--rehype:className=wrap-text -->
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="repeatuntil-循环"><a aria-hidden="true" tabindex="-1" href="#repeatuntil-循环"><span class="icon icon-link"></span></a>repeat...until 循环</h3><div class="wrap-body">
|
||
<p>repeat...until 循环的条件语句在当前循环结束后判断</p>
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> num <span class="token operator">=</span> <span class="token number">11</span>
|
||
</span><span class="code-line"><span class="token keyword">repeat</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"num 的值为: "</span><span class="token punctuation">,</span> num<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> num <span class="token operator">=</span> num <span class="token operator">+</span> <span class="token number">1</span>
|
||
</span><span class="code-line"><span class="token keyword">until</span> <span class="token punctuation">(</span>num <span class="token operator">></span> <span class="token number">10</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">-- num 的值为：11</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="break"><a aria-hidden="true" tabindex="-1" href="#break"><span class="icon icon-link"></span></a>break</h3><div class="wrap-body">
|
||
<pre class="language-lua"><code class="language-lua code-highlight"><span class="code-line"><span class="token keyword">local</span> num <span class="token operator">=</span> <span class="token number">11</span>
|
||
</span><span class="code-line"><span class="token keyword">repeat</span>
|
||
</span><span class="code-line"> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"num 的值为: "</span><span class="token punctuation">,</span> num<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> num <span class="token operator">=</span> num <span class="token operator">+</span> <span class="token number">1</span>
|
||
</span><span class="code-line"> <span class="token keyword">if</span> <span class="token punctuation">(</span>num <span class="token operator">></span> <span class="token number">15</span><span class="token punctuation">)</span> <span class="token keyword">then</span>
|
||
</span><span class="code-line"> <span class="token keyword">break</span>
|
||
</span><span class="code-line"> <span class="token keyword">end</span>
|
||
</span><span class="code-line"><span class="token keyword">until</span> <span class="token punctuation">(</span>num <span class="token operator">></span> <span class="token number">20</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div></div></div><div class="wrap h2body-not-exist"><div class="wrap-header h2wrap"><h2 id="另见"><a aria-hidden="true" tabindex="-1" href="#另见"><span class="icon icon-link"></span></a>另见</h2><div class="wrap-body">
|
||
<ul>
|
||
<li><a href="http://www.lua.org">Lua</a></li>
|
||
<li><a href="https://wiki.luatos.com/luaGuide/introduction.html">luatos</a></li>
|
||
<li><a href="https://www.twle.cn/l/yufei/lua53/lua-basic-index.html">Lua 教程</a></li>
|
||
</ul>
|
||
</div></div><div class="h2wrap-body"></div></div></div></div><footer class="footer-wrap"><footer class="max-container">© 2022 Kenny Wang.</footer></footer><script>
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|
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|
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|
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const anchorContainer = document.querySelectorAll('.menu-tocs .menu-modal a.tocs-link');
|
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|
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|
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|
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const anchor = element || document.querySelector(`a.tocs-link[href='${decodeURIComponent(window.location.hash)}']`);
|
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|
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|
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