<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Metaclass on 技术笔记</title><link>https://elliot-blog.com/tags/metaclass/</link><description>Recent content in Metaclass on 技术笔记</description><generator>Hugo</generator><language>zh-CN</language><lastBuildDate>Sun, 18 Jan 2026 02:24:22 +0800</lastBuildDate><atom:link href="https://elliot-blog.com/tags/metaclass/index.xml" rel="self" type="application/rss+xml"/><item><title>Python 深度进阶：元类 (Metaclass) 与属性查找机制解析</title><link>https://elliot-blog.com/posts/202512/python_metaclass/</link><pubDate>Sat, 20 Dec 2025 19:36:02 +0800</pubDate><guid>https://elliot-blog.com/posts/202512/python_metaclass/</guid><description>&lt;h1 id="python-深度进阶元类-metaclass-与属性查找机制解析"&gt;Python 深度进阶：元类 (Metaclass) 与属性查找机制解析&lt;/h1&gt;
&lt;h2 id="metaclass"&gt;metaclass&lt;/h2&gt;
&lt;div class="code-block code-line-numbers open" style="counter-reset: code-block 0"&gt;
 &lt;div class="code-header language-pyt"&gt;
 &lt;span class="code-title"&gt;&lt;i class="arrow fas fa-angle-right fa-fw" aria-hidden="true"&gt;&lt;/i&gt;&lt;/span&gt;
 &lt;span class="ellipses"&gt;&lt;i class="fas fa-ellipsis-h fa-fw" aria-hidden="true"&gt;&lt;/i&gt;&lt;/span&gt;
 &lt;span class="copy" title="复制到剪贴板"&gt;&lt;i class="far fa-copy fa-fw" aria-hidden="true"&gt;&lt;/i&gt;&lt;/span&gt;
 &lt;/div&gt;&lt;div class="highlight"&gt;&lt;pre tabindex="0" class="chroma"&gt;&lt;code class="language-fallback" data-lang="fallback"&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;class M(type):
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; @classmethod
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; def __prepare__(metacls, name, bases, **kwargs):
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; namespace = dict()
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; # 注入一个工具函数，类定义体里可以直接用
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; namespace[&amp;#39;add&amp;#39;] = lambda a, b: a + b
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; namespace[&amp;#39;BASE_VALUE&amp;#39;] = 100
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; return namespace
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;class Test(metaclass=M):
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; result = add(1, 2) 
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; total = BASE_VALUE + 50 
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt; 
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;test = Test()
&lt;/span&gt;&lt;/span&gt;&lt;span class="line"&gt;&lt;span class="cl"&gt;print(Test.result) #3&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;p&gt;这里是一个元类,这里直接塞入了一个add方法,这样所有被这个元类创建的类都可以使用这个方法&lt;/p&gt;</description></item></channel></rss>