class?A:
????pass

a?=?A()
a.xxx
"""
AttributeError:?'A'?object?has?no?attribute?'xxx'
"""

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?get_info(self):
????????return?f"name:?{self.name},?age:?{self.age}"

????def?__getattr__(self,?item):
????????return?f"你訪問了?{item}?屬性"


girl?=?Girl()
print(girl.name,?girl.age)??#?古明地覺?17
print(girl.get_info)??#?<bound?method?Girl.get_info...>
print(girl.get_info())??#?name:?古明地覺,?age:?17

print(girl.xxx)??#?你訪問了?xxx?屬性
print(girl.yyy)??#?你訪問了?yyy?屬性
print(girl.zzz)??#?你訪問了?zzz?屬性

def?__getattr__(name):
????return?f"{__name__}?中不存在?{name}"

name?=?"古明地覺"
age?=?17

from?tools?import?name,?age,?xxx,?yyy

print(name,?age)??#?古明地覺?17
print(xxx)??#?tools?中不存在?xxx
print(yyy)??#?tools?中不存在?yyy

import?tools
print(tools.zzz)??#?tools?中不存在?zzz

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?__getattribute__(self,?item):
????????return?f"獲取屬性:?{item}"


girl?=?Girl()
print(girl.name)??#?獲取屬性:?name
print(girl.age)??#?獲取屬性:?age
print(girl.xxx)??#?獲取屬性:?xxx

#?即便你想通過屬性字典獲取也是沒有用的
#?因為不管什么屬性，都會執(zhí)行?__getattribute__
print(girl.__dict__)??#?獲取屬性:?__dict__

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?__getattribute__(self,?item):
????????return?getattr(self,?item)


girl?=?Girl()
print(girl.name)
#?顯然上面的代碼會陷入無限遞歸
#?因為?girl.name?會調用?__getattribute__
#?而在里面又執(zhí)行了?getattr(self,?item)，還是在獲取屬性
#?所以又會調用?__getattribute__，于是會無限遞歸

#?可能有人說，那我換一種方式
#?我將?getattr(self,?item)?改成?self.__dict__[item]?可以嗎
#?答案也是不行的，因為?self.__dict__?仍是在獲取屬性
#?只要獲取屬性，就會觸發(fā)?__getattribute__，依舊會陷入無限遞歸

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?__getattribute__(self,?item):
????????return?super().__getattribute__(item)


girl?=?Girl()
print(girl.name)
print(girl.age)
try:
????girl.xxx
except?AttributeError:
????print("屬性?xxx?不存在")
"""
古明地覺
17
屬性?xxx?不存在
"""

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?__getattr__(self,?item):
????????print(f"__getattr__?{item}")
????????return?f"獲取屬性?{item}"

????def?__getattribute__(self,?item):
????????print(f"__getattribute__?{item}")
????????return?super().__getattribute__(item)


girl?=?Girl()
#?不管屬性是否存在，一律調用?__getattribute__
#?然后在里面我們又調用了父類的?__getattribute__
#?那么會檢測屬性是否存在，存在則直接獲取對應的值，然后返回
print(girl.name)
"""
__getattribute__?name
古明地覺
"""
#?age?也是相同的邏輯，和?name?一樣，這兩個屬性都是存在的
print(girl.age)
"""
__getattribute__?age
17
"""

#?依舊執(zhí)行?__getattribute__，然后調用父類的?__getattribute__
#?由于屬性?xxx?不存在，于是會執(zhí)行?__getattr__
print(girl.xxx)
"""
__getattribute__?xxx
__getattr__?xxx
獲取屬性?xxx
"""

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?__getattr__(self,?item):
????????return?f"屬性?{item}?不存在"

????def?__getattribute__(self,?item):
????????if?item?==?"age":
????????????return?"女人芳齡不可泄露，別問，問就是還不到?18?歲"
????????return?super().__getattribute__(item)


girl?=?Girl()
#?name?屬性存在，所以在?__getattribute__?中直接返回
print(girl.name)
"""
古明地覺
"""
#?age?也是如此，也是在?__getattribute__?中直接返回
#?只不過它相當于被攔截了
print(girl.age)
"""
女人芳齡不可泄露，別問，問就是還不到?18?歲
"""
#?父類在執(zhí)行?__getattribute__?的時候，發(fā)現(xiàn)?xxx?屬性不存在
#?于是會觸發(fā)?__getattr__?的執(zhí)行（如果沒定義則拋出?AttributeError）
print(girl.xxx)
"""
屬性?xxx?不存在
"""

class?Girl:

????def?__init__(self):
????????self.name?=?"古明地覺"
????????self.age?=?17

????def?get_info(self):
????????return?f"name:?{self.name},?age:?{self.age}"

????def?__getattribute__(self,?item):
????????if?item?==?"get_info":
????????????return?"此方法禁止獲取"
????????return?super().__getattribute__(item)


girl?=?Girl()
print(girl.get_info)
"""
此方法禁止獲取
"""
#?默認情況下?girl.get_info?拿到的是一個方法
#?然后再加上小括號就會執(zhí)行該方法
#?但在?__getattribute__?中我們將其攔截了，并返回一個字符串
#?所以此時?girl.get_info()?就會報錯，因為字符串無法被調用