调用类中原本没有定义的属性时候，调用__getattr__
class Cat(object):
def __init__(self):
self.name = "jn"
def __getattr__(self, item):
return "tm"
cat = Cat()
print(cat.name)
print(getattr(cat, ‘name‘))
print("*" * 20)
print(cat.age)
print(getattr(cat, ‘age‘))
#对实例的属性进行赋值的时候调用__setattr__
class Dict(dict):
def __getattr__(self, key):
try:
return self[key]
except KeyError:
raise AttributeError(r"‘Dict‘ object has no attribute ‘%s‘" % key)
def __setattr__(self, key, value):
self[key] = value
d = Dict(a=1, b=2)
print (d[‘a‘])
print (d.a)
d.a = 100
print (d[‘a‘])
python __getattr__, __setattr__
原文：https://www.cnblogs.com/honglingjin/p/12108722.html