Python编程：类的实例动态增加属性和方法

# -*- coding: utf-8 -*-

# @File    : 类的实例动态增加属性和方法.py
# @Date    : 2018-05-31
# @Author  : Peng Shiyu

class Person(object):
    count = 0
    def __init__(self, name):
        self.name = name


if __name__ == '__main__':
    # 实例化
    p1 = Person("tom")
    print(p1.name)  # tom
    print(p1.count)  # 0

    p2 = Person("jack")
    print(p2.name)  # jack
    print(p2.count)  # 0

    # 通过实例修改类变量
    p1.count = 2
    print(p1.count)  # 2
    print(p1.count)  # 2
    print(Person.count)  # 0

    # 通过类修改类变量
    Person.count = 3
    print(p1.count)  # 2
    print(p1.count)  # 2
    print(Person.count)  # 3

    # 给实例增加属性
    p1.age = 23
    print(p1.age)  # 23

    # 给实例增加方法
    def set_age(self, age):
        self.age = age

    from types import MethodType
    p1.set_age = MethodType(set_age, p1)
    p1.set_age(25)

    print(p1.age)  # 25

    print(p2.age)
    # AttributeError: 'Person' object has no attribute 'age'