解密Python元编程：从基础到高阶典范

def add_method_to_class(cls):def new_method(self):print("This is a new method")setattr(cls, "new_method", new_method)return cls@add_method_to_classclass MyClass:passobj = MyClass()obj.new_method()# This will print "This is a new method"

class MetaClass(type):def __new__(cls, name, bases, attrs):print("Creating a new class named {}".fORMat(name))return super(MetaClass, cls).__new__(cls, name, bases, attrs)class MyClass(object, metaclass=MetaClass):pass

def create_function(name):code = """def {}(x):return x + 1"""exec(code.format(name))return locals()[name]add_one = create_function("add_one")print(add_one(5))# Output: 6

def generate_class(name, attributes):code = """class {}:"""for attribute, value in attributes.items():code += "{} = {}".format(attribute, value)exec(code.format(name))return locals()[name]MyClass = generate_class("MyClass", {"x": 1, "y": 2})obj = MyClass()print(obj.x, obj.y)# Output: 1 2

class MyClass:def __add__(self, other):return self.x + other.xobj1 = MyClass()obj1.x = 1obj2 = MyClass()obj2.x = 2print(obj1 + obj2)# Output: 3