add python_metaclass.py

README.md

@@ -23,6 +23,8 @@
 ### python_decorator.py: Python进阶: 通过实例详解装饰器（附代码）
 
 ### python_datetime.py: 你真的了解Python中的日期时间处理吗？
+
+### python_metaclass.py: Python进阶: 一步步理解Python中的元类metaclass
 ===============================================================================
 
 ### 您可以fork该项目,并在修改后提交Pull request

python_metaclass.py

@@ -0,0 +1,55 @@
+# _*_ coding: utf-8 _*_
+
+"""
+python_metaclass.py by xianhu
+"""
+
+
+class Foo:
+    def hello(self):
+        print("hello world!")
+        return
+
+foo = Foo()
+print(type(foo))            # <class '__main__.Foo'>
+print(type(foo.hello))      # <class 'method'>
+print(type(Foo))            # <class 'type'>
+
+temp = Foo                  # 赋值给其他变量
+Foo.var = 11                # 增加参数
+print(Foo)                  # 作为函数参数
+
+
+# ========================================================================
+def init(self, name):
+    self.name = name
+    return
+
+
+def hello(self):
+    print("hello %s" % self.name)
+    return
+
+Foo = type("Foo", (object,), {"__init__": init, "hello": hello, "cls_var": 10})
+foo = Foo("xianhu")
+print(foo.hello())
+print(Foo.cls_var)
+
+print(foo.__class__)
+print(Foo.__class__)
+print(type.__class__)
+# ========================================================================
+
+
+class Author(type):
+    def __new__(mcs, name, bases, dict):
+        # 添加作者属性
+        dict["author"] = "xianhu"
+        return super(Author, mcs).__new__(mcs, name, bases, dict)
+
+
+class Foo(object, metaclass=Author):
+    pass
+
+foo = Foo()
+print(foo.author)