我要评论修改类方法
直接将函数绑定到原有的方法上，函数的第一个参数依然是实例self，修改后的方法不仅会作用于新创建的实例，也会作用于修改前创建的实例。
class Student:
def __init__(self, name):
self.name = name
def self_introduce(self):
print(f'I am {self.name}.')
def new_self_introduce(self):
print(f'My name is {self.name}. Nice to meet you!')
a = Student('xiaoming')
a.self_introduce()
Student.self_introduce = new_self_introduce
a.self_introduce()
b = Student('xiaohong')
b.self_introduce()
输出：
I am xiaoming.
My name is xiaoming. Nice to meet you!
My name is xiaohong. Nice to meet you!
修改实例方法
若采用与上述相同的方式绑定
a.self_introduce = new_self_introduce
a.self_introduce()
则会出现错误
Traceback (most recent call last):
File “C:/Users/hmy/Documents/git/doc/spiders/hmyspiders/Script/test.py”, line 18, in <module>
a.self_introduce()
TypeError: new_self_introduce() missing 1 required positional argument: ‘self’
可见实例对象并没有作为参数传入新方法的self中，所以这种方法只能绑定不需要self参数的静态方法。这时可以用types中的MethodType函数来处理，参数为要绑定的新方法,实例，只作用于当前实例
from types import MethodType
class Student:
def __init__(self, name):
self.name = name
def self_introduce(self):
print(f'I am {self.name}.')
def new_self_introduce(self):
print(f'My name is {self.name}. Nice to meet you!')
a = Student('xiaoming')
a.self_introduce()
a.self_introduce = MethodType(new_self_introduce, a)
a.self_introduce()
b = Student('xiaohong')
b.self_introduce()
输出:
I am xiaoming.
My name is xiaoming. Nice to meet you!
I am xiaohong.
本文地址：https://blog.csdn.net/jerrism/article/details/107357541
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