__str__函数
def __str__(self): return str_type参数：无 返回值：一般返回对于该类的描述信息
__getattr__函数
def __getattr__(self, key): print(something.….)参数:
key: 调用任意不存在的属性名
返回值:可以是任意类型也可以不进行返回
__setattr__函数
def __settattr__(self, key,value): self._dict_[key] = value参数:
key当前的属性名
value 当前的参数对应的值
返回值: 无
__call__函数
def __call__(self,*args,**kwargs): print( 'call will start')参数: 可传任意参数 返回值: 与函数情况相同可有可无
实战
#!/usr/bin/python3
# -*- coding: utf-8 -*-
# @Time : 2021/8/15 18:22
# @Author : InsaneLoafer
# @File : object_func.py
class Test(object):
def __str__(self):
return 'this is a test class'
def __getattr__(self, key):
return '这个key：{}并不存在'.format(key)
def __setattr__(self, key, value):
print(key, value)
self.__dict__[key] = value
print(self.__dict__)
def __call__(self, *args, **kwargs):
print('call will start')
print(args, kwargs)
t = Test()
print(t)
print(t.a) # 不存在的对象会直接打印出来，而不是报错
t.name = 'insane'
t(123, name='loafer')
"""实现链式操作"""
class Test2(object):
def __init__(self, attr=''):
self.__attr = attr
def __call__(self, name):
print('key is {}'.format(self.__attr))
return name
def __getattr__(self, key):
if self.__attr:
key = '{}.{}'.format(self.__attr, key)
else:
key = key
print(key)
return Test2(key) # 递归操作
t2 = Test2()
print(t2.a.c('insane'))
this is a test class
这个key：a并不存在
name insane
{'name': 'insane'}
call will start
(123,) {'name': 'loafer'}
a
a.c
key is a.c
insane
Process finished with exit code 0
