Python动态创建类实例详解

MyClass = type('MyClass', (), {'attribute': 10})
obj = MyClass()
print(obj.attribute)  # 输出: 10

def new_method(self):
    return "New method added dynamically!"
MyClass.new_method = new_method
obj = MyClass()
print(obj.new_method())  # 输出: "New method added dynamically!"

class MyMeta(type):
    def __new__(cls, name, bases, dct):
        dct['new_attribute'] = 20
        return super().__new__(cls, name, bases, dct)
class MyDynamicClass(metaclass=MyMeta):
    pass
obj = MyDynamicClass()
print(obj.new_attribute)  # 输出: 20

from collections import namedtuple
# 创建一个名为Person的NamedTuple
Person = namedtuple('Person', ['name', 'age'])
# 动态创建一个新类，用于扩展Person
NewPerson = type('NewPerson', (Person,), {'gender': 'Male'})
obj = NewPerson('Alice', 30)
print(obj.name, obj.age, obj.gender)  # 输出: Alice 30 Male

def add_method(cls):
    def new_method(self):
        return f"Hello, I'm {self.name}!"
    cls.new_method = new_method
    return cls
@add_method
class Greeting:
    def __init__(self, name):
        self.name = name
obj = Greeting('Tom')
print(obj.new_method())  # 输出: Hello, I'm Tom!