二、特殊成员
__init__ 类() 自动执行
__del__ 析构方法
__call__ 对象() 类()() 自动执行
__int__ int(对象)
__str__ str()
__add__
__dict__ 字典，将对象中封装的所有内容通过字典的形式返回
__getitem__ 切片(slice类型)或索引
__setitem__
__delitem__
__iter__ 迭代
#如果类中有__iter__方法，对象=>>可迭代对象
#对象,__iter__()的返回值：迭代器
#for 循环，迭代器，nex
#for 循环，可迭代对象，对象.__iter__(),迭代器，next
#1、执行li对象的类F类中的__iter__方法，并获取其返回值
#2、循环上一步中的返回的对象
__call__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self):
print('init')
obj = Foo()
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
init
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self):
print('init')
obj = Foo()
obj()
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
init
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 12, in <module>
obj()
TypeError: 'Foo' object is not callable
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self):
print('init')
def __call__(self, *args, **kwargs):
print('call')
obj = Foo()
obj()
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
init
call
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self):
print('init')
def __call__(self, *args, **kwargs):
print('call')
# obj = Foo()
# obj()
Foo()()
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
init
call
Process finished with exit code 0
__int__
s = "123"
# s = str('123')
i = int(s)
print(i,type(i))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123 <class 'int'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo():
def __init__(self):
pass
obj = Foo()
print(obj,type(obj))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f857d05b3d0> <class '__main__.Foo'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo():
def __init__(self):
pass
obj = Foo()
print(obj,type(obj))
r = int(obj)
print(r)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f93190bb3d0> <class '__main__.Foo'>
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 14, in <module>
r = int(obj)
TypeError: int() argument must be a string, a bytes-like object or a number, not 'Foo'
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo():
def __init__(self):
pass
def __int__(self):
return 1
obj = Foo()
print(obj,type(obj))
r = int(obj)
print(r)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f1524dff3d0> <class '__main__.Foo'>
1
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo():
def __init__(self):
pass
def __int__(self):
return 1111
obj = Foo()
print(obj,type(obj))
# int,对象，自动执行对象的__int__方法，并将返回值赋值给int对象
r = int(obj)
print(r)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f69912413d0> <class '__main__.Foo'>
1111
Process finished with exit code 0
__str__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo():
def __init__(self):
pass
def __int__(self):
return 1111
def __str__(self):
return 'smoke'
obj = Foo()
print(obj,type(obj))
# int,对象，自动执行对象的__int__方法，并将返回值赋值给int对象
r = int(obj)
print(r)
i = str(obj)
print(i)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
smoke <class '__main__.Foo'>
1111
smoke
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,n,a):
self.name = n
self.age = a
obj = Foo('smoke',18)
print(obj)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7fe15519f3d0>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,n,a):
self.name = n
self.age = a
def __str__(self):
return self.name
obj = Foo('smoke',18)
print(obj)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
smoke
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,n,a):
self.name = n
self.age = a
def __str__(self):
return '%s-%s' % (self.name,self.age)
obj = Foo('smoke',18)
print(obj) #print(str(obj)) str(obj) obj中__str__,并获取其返回值
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
smoke-18
Process finished with exit code 0
__add__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 15, in <module>
r = obj1 + obj2
TypeError: unsupported operand type(s) for +: 'Foo' and 'Foo'
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
return 123
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123 <class 'int'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
# sel = obj1(smoke,19)
# other = obj2('cherry',66)
return 'xxoo'
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
#两个对象相加时，自动执行第一个对象的__add__方法，并且将第二个对象当作参数传入
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
xxoo <class 'str'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
return self.age + other.age
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
85 <class 'int'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
# return self.age + other.age
return Foo('tt',99)
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f110935d640> <class '__main__.Foo'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
# return self.age + other.age
# return Foo('tt',99)
return Foo(obj1.name,other.age)
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f9c25a6a640> <class '__main__.Foo'>
Process finished with exit code 0
__del__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __add__(self, other):
# return self.age + other.age
# return Foo('tt',99)
return Foo(obj1.name,other.age)
def __del__(self):
print('析构方法') #对象被销毁()时，自动执行
obj1 = Foo('smoke',19)
obj2 = Foo('cherry',66)
r = obj1 + obj2
print(r,type(r))
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
<__main__.Foo object at 0x7f0822e69b50> <class '__main__.Foo'>
析构方法
析构方法
析构方法
Process finished with exit code 0
__dict__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
self.n = 123
obj = Foo('smoke',18)
d = obj.__dict__
print(d)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
{'name': 'smoke', 'age': 18, 'n': 123}
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
self.n = 123
# obj = Foo('smoke',18)
#
# d = obj.__dict__
# print(d)
ret = Foo.__dict__
print(ret)
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
'''
当前类是干嘛的。。。
'''
def __init__(self,name,age):
self.name = name
self.age = age
self.n = 123
# obj = Foo('smoke',18)
#
# d = obj.__dict__
# print(d)
ret = Foo.__dict__
print(ret)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
{'__module__': '__main__', '__doc__': '\n 当前类是干嘛的。。。\n ', '__init__': <function Foo.__init__ at 0x7fc5d63a71f0>, '__dict__': <attribute '__dict__' of 'Foo' objects>, '__weakref__': <attribute '__weakref__'
of 'Foo' objects>}
Process finished with exit code 0
__getitem__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
li = [11,22,33,44]
li = list([11,22,33,44])
r1 = li[3]
print(r1)
li[3] = 666
del li[2]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
44
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
li = Foo('smoke',18)
li[8]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 13, in <module>
li[8]
TypeError: 'Foo' object is not subscriptable
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
return item + 10
li = Foo('smoke',18)
r = li[8] #自动执行li对象的类中的__getitem__方法，8当作参数传递给item
print(r)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
18
Process finished with exit code 0
__setitem__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
return item + 10
li = Foo('smoke',18)
r = li[8] #自动执行li对象的类中的__getitem__方法，8当作参数传递给item
print(r)
li[100] = 123
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
18
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 19, in <module>
li[100] = 123
TypeError: 'Foo' object does not support item assignment
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
return item + 10
def __setitem__(self, key, value):
print(key,value)
li = Foo('smoke',18)
r = li[8] #自动执行li对象的类中的__getitem__方法，8当作参数传递给item
print(r)
li[100] = "asdf"
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
18
100 asdf
Process finished with exit code 0
__delitem__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
return item + 10
def __setitem__(self, key, value):
print(key,value)
li = Foo('smoke',18)
r = li[8] #自动执行li对象的类中的__getitem__方法，8当作参数传递给item
print(r)
li[100] = "asdf"
del li[999]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
18
100 asdf
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 24, in <module>
del li[999]
AttributeError: __delitem__
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
return item + 10
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
r = li[8] #自动执行li对象的类中的__getitem__方法，8当作参数传递给item
print(r)
li[100] = "asdf"
del li[999]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
18
100 asdf
999
Process finished with exit code 0
索引和切片
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
print(item,type(item))
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123 <class 'int'>
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
print(item,type(item))
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
li[999] = 'smoke'
del li[234]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123 <class 'int'>
999 smoke
234
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
print(item,type(item))
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
li[1:4:2]
li[999] = 'smoke'
del li[234]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123 <class 'int'>
slice(1, 4, 2) <class 'slice'>
999 smoke
234
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
# 如果item是基本类型：int, str, 索引获取
# slice对象的话，切片
if type(item) == slice:
print('调用者希望内部做切片处理')
else:
print('调用者希望内部做索引处理')
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
li[1:4:2]
# class Slice:
# def __init__(self,a,b,c):
# self.start = a
# self.end = b
# self.step = c
#
# obj = Slice(1,4,2)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
调用者希望内部做索引处理
调用者希望内部做切片处理
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
# 如果item是基本类型：int, str, 索引获取
# slice对象的话，切片
if type(item) == slice:
print(item.start)
print(item.stop)
print(item.step)
print('调用者希望内部做切片处理')
else:
print('调用者希望内部做索引处理')
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
li[1:4:2]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
调用者希望内部做索引处理
1
4
2
调用者希望内部做切片处理
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __getitem__(self, item):
# return item + 10
# 如果item是基本类型：int, str, 索引获取
# slice对象的话，切片
if type(item) == slice:
print(item.start)
print(item.stop)
print(item.step)
print('调用者希望内部做切片处理')
else:
print('调用者希望内部做索引处理')
def __setitem__(self, key, value):
print(key,value)
def __delitem__(self, key):
print(key)
li = Foo('smoke',18)
li[123]
li[1:4:2]
li[1:3] =[11,22]
del li[1:3]
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
调用者希望内部做索引处理
1
4
2
调用者希望内部做切片处理
slice(1, 3, None) [11, 22]
slice(1, 3, None)
Process finished with exit code 0
__iter__
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
li = [11,22,33,44]
for item in li:
print(item)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
11
22
33
44
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
li = [11,22,33,44]
li = list([11,22,33,44])
for item in li:
print(item)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
11
22
33
44
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
li = Foo('smoke',18)
for i in li:
print(i)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 14, in <module>
for i in li:
TypeError: 'Foo' object is not iterable
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __iter__(self):
return [11,22,33]
li = Foo('smoke',18)
# 1、执行li对象的Foo类中的__iter__方法，并获取其返回值
# 2、循环上一步中返回的对象
for i in li:
print(i)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
Traceback (most recent call last):
File "/home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py", line 17, in <module>
for i in li:
TypeError: iter() returned non-iterator of type 'list'
Process finished with exit code 1
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
i = iter([11,22,33,44])
print(next(i))
print(next(i))
print(next(i))
print(next(i))
# i,迭代器
for item in i:
print(item)
# i,可迭代对象，执行对象的__iter__方法，获取迭代器
for item in i:
print(item)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
11
22
33
44
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo:
def __init__(self,name,age):
self.name = name
self.age = age
def __iter__(self):
return iter([11,22,33])
li = Foo('smoke',18)
# 如果类中有__iter__方法，就叫可迭代对象
# 对象.__iter__()的返回值，是一个迭代器
# for 循环遇到迭代器执行next()
# for循环遇到可迭代对象，对象.__iter__(),迭代器,next
# 1、执行li对象的Foo类中的__iter__方法，并获取其返回值
# 2、循环上一步中返回的对象
for i in li:
print(i)
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
11
22
33
Process finished with exit code 0
三、metaclass，类的祖宗（原始类）
a.Python中一切事物都是对象
b.
class Foo:
pass
obj = Foo()
# obj是对象
# Foo类也是一个对象，type的对象
c.
类都是type累的对象 type(..)
"对象"都是累的对象 类()
# 声明了一个类
class Foo:
def function(self):
print(123)
Foo = type('Foo',(object,),{'func':function})
# type('Foo',(object,),{'func': lambda x: 123}) 声明一个类，类中有一个成员func
Foo = type('Foo',(object,),{'func': lambda x: 123})
obj = Foo()
1、type类中的init方法，然后创建对象
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class Foo(object):
def func(self):
print('hello smoke')
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class MyType(type):
def __init__(self,*args,**kwargs):
print(123)
class Foo(object,metaclass=MyType): #创建这个类用Mytype创建
def func(self):
print('hello smoke')
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class MyType(type):
def __init__(self,*args,**kwargs):
print(123)
def __call__(self, *args, **kwargs):
print('456')
class Foo(object,metaclass=MyType):
def __init__(self):
pass
def func(self):
print('hello smoke')
obj = Foo()
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123
456
Process finished with exit code 0
#!/usr/bin/env python3.8
# -*- coding: UTF-8 -*-
# __author:smoke
# file:special_members.py
# time:2021/03/02
class MyType(type):
def __init__(self,*args,**kwargs):
# self=Foo
print(123)
def __call__(self, *args, **kwargs):
# self=Foo
r = self.__new__()
class Foo(object,metaclass=MyType):
def __init__(self):
pass
def __new__(cls, *args, **kwargs):
return '对象'
def func(self):
print('hello smoke')
/usr/bin/python3.8 /home/smoke/PycharmProjects/pythonProject/lean_python/special_members.py
123
Process finished with exit code 0
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