# _開頭： 私有變量；
# __開問： 私有變量，不能被繼承；
# __xxx__： 能被訪問，不能被繼承；
class A:
def __init__(self):
self._internal = 0 # 私有變量不能被訪問
self.public = 1 # 可被訪問
def public_method(self):
pass
def _private_method(self): # 私有方法不能被訪問
pass
class B:
def __init__(self):
self.__private = 0 # 這個(gè)屬性會(huì)在內(nèi)存中被重新命名為_B__private

def __private_method(self): # 不能被訪問，不能被繼承
pass
def __private_method__(self): # 能被訪問，不能被繼承
pass

class Dog:
a = "0"; #相當(dāng)于public static變量,全局的
"""__init__是一個(gè)默認(rèn)的方法，且self為默認(rèn)的，用self修飾的屬性為public類型的類變量"""
def __init__(self, name, age):
self.name = name
self.age = age
self.sex = "1";#設(shè)置屬性默認(rèn)值

def sit(self):
print(self.name + "is now sitting" + "and sex is " + self.sex + Dog.a)

@classmethod
def user_name(cls, name): #注意這種注解的用法
return cls()

dog = Dog("kk", 12);
dog.sit()

from collections import OrderedDict; #使用標(biāo)準(zhǔn)類庫
t = OrderedDict();

class Date:
# Primary constructor
def __init__(self, year, month, day):
self.year = year
self.month = month
self.day = day

# Alternate constructor
@classmethod
def today(cls):
t = time.localtime() #它接收一個(gè)class作為第一個(gè)參數(shù)，它被用來創(chuàng)建并返回最終的實(shí)例， 這個(gè)cls==__init__
return cls(t.tm_year, t.tm_mon, t.tm_mday)

a = Date(2020, 5, 10) # Primary
b = Date.today() # Alternate

class Structure1:
# Class variable that specifies expected fields
_field_list = []

def __init__(self, *args):
if len(args) != len(self._field_list):
raise TypeError(f'Expected {len(self._field_list)} arguments')
# Set the arguments
for name, value in zip(self._field_list, args):
setattr(self, name, value)

# Example class definitions
class Course(Structure1):
# 這行只是為了一個(gè)準(zhǔn)許入判斷，沒有太多實(shí)際意思，或是一個(gè)聲明
_field_list = ['course_name', 'total_class', 'score']

c = Course('python', 30, 0.3);

class Structure2:
_field_list = []

def __init__(self, *args, **kwargs):
if len(args) > len(self._field_list):
raise TypeError(f'Expected {len(self._field_list)} arguments')
# Set all of the positional arguments
for name, value in zip(self._field_list, args):
setattr(self, name, value)

# Set the remaining keyword arguments
#是通過pop這種方式來檢查的，在長度范圍內(nèi)如果pop出錯(cuò)則拋異常
for name in self._field_list[len(args):]:
setattr(self, name, kwargs.pop(name))

# Check for any remaining unknown arguments
if kwargs:
raise TypeError(f"Invalid argument(s): {','.join(kwargs)}")

# Example use
class Course(Structure2):
_field_list = ['course_name', 'total_class', 'score']

course_1 = Course('python', 30, 0.3)
course_2 = Course('python', 30, score=0.3)
course_3 = Course('python', total_class=30, score=0.3)

class Structure3:
# Class variable that specifies expected fields
_field_list = []

def __init__(self, *args, **kwargs):
if len(args) != len(self._field_list):
raise TypeError(f'Expected {len(self._field_list)} arguments')

# Set the arguments
for name, value in zip(self._field_list, args):
setattr(self, name, value)

# Set the additional arguments (if any)
extra_args = kwargs.keys() - self._field_list
for name in extra_args:
setattr(self, name, kwargs.pop(name))

if kwargs:
raise TypeError(f"Duplicate values for {','.join(kwargs)}")

# Example use
if __name__ == '__main__':
class Course(Structure3):
_field_list = ['course_name', 'total_class', 'score']

course_1 = Course('python', 30, 0.3)
course_2 = Course('python', 30, 0.3, date='8/5/2020')

# Descriptor attribute for an integer type-checked attribute
class Integer:
def __init__(self, name):
self.name = name
"""下面三個(gè)方法只是一個(gè)更嚴(yán)格的定義，可以不需要，要使用上面的描述器，需要把描述器放入到一個(gè)class中，這樣所有對描述器的訪問都會(huì)被get/set/delete所捕獲"""
def __get__(self, instance, cls):
if not instance:
return self
else:
return instance.__dict__[self.name]
def __set__(self, instance, value):
if not isinstance(value, int):
raise TypeError('Expected an int object')
instance.__dict__[self.name] = value
def __delete__(self, instance):
del instance.__dict__[self.name]

class Point:
"""實(shí)例變量，和下面的x,y不是一回事"""
x = Integer('x')
y = Integer('y')

def __init__(self, x, y):
self.x = x
self.y = y
print(Point.x.name) # x
point = Point(3, 5)
print(f'point x = {point.x}') #3
print(f'point y = {point.y}') #5
point.y = 6
print(f'after change,point y = {point.y}') #6

class A:
def __init__(self):
self.x = 0
class B(A):
def __init__(self):
super().__init__() #這行需要注意，也可以不寫，但不寫時(shí)就不會(huì)調(diào)用父類的init方法
self.y = 1

class Base:
def __init__(self):
print('call Base.__init__')
class A(Base):
def __init__(self):
Base.__init__(self)
print('call A.__init__')

class B(Base):
def __init__(self):
Base.__init__(self)
print('call B.__init__')
"""多繼承的實(shí)現(xiàn)"""
class C(A,B):
def __init__(self):
A.__init__(self)
B.__init__(self)
print('call C.__init__')
c = C()
# call Base.__init__
# call A.__init__
# call Base.__init__
# call B.__init__
# call C.__init__

class Proxy:
def __init__(self, obj):
self._obj = obj

def __getattr__(self, name):
return getattr(self._obj, name)

def __setattr__(self, name, value):
if name.startswith('_'):
"""調(diào)用父類方法"""
super().__setattr__(name, value)
else:
setattr(self._obj, name, value)

proxy = Proxy({})
proxy.__setattr__("_name", "hm")

# 父類
class Person:
def __init__(self, name):
self.name = name

# defined Getter function， auto to call the sign name.setter when it be build
@property
def name(self):
return self._name

# defined Setter function
@name.setter
def name(self, value):
if not isinstance(value, str):
raise TypeError('Expected a string')
self._name = value

# defined Deleter function
@name.deleter
def name(self):
raise AttributeError("Can't delete attribute")

"""子類"""
class SubPerson(Person):
@property
def name(self):
print('Getting name')
return super().name

@name.setter
def name(self, value):
print(f'Setting name to {value}')
super(SubPerson, SubPerson).name.__set__(self, value)

@name.deleter
def name(self):
print('Deleting name')
super(SubPerson, SubPerson).name.__delete__(self)

"""測試"""
sub_person = SubPerson('Guido')
print(f'name is: {sub_person.name}')

class SubPerson(Person):
@Person.name.getter
def name(self):
print('Getting name')
return super().name # or super(SubPerson, SubPerson).name.__set__(self, value)
sub_p = SubPerson('Bill')

#不能用property的原因是，property其實(shí)是get、set、del函數(shù)的集合，各有各的用處。下面才是正確的擴(kuò)展方式，所以下面的代碼是不工作的
class SubPerson(Person):
@property # Doesn't work
def name(self):
print('Getting name')
return super().name
#如果要用property屬性則要用下面的編碼實(shí)現(xiàn)
class SubPerson(Person):
@property
def name(self):
print('Getting name')
return super().name
@name.setter
def name(self, value):
print(f'Setting name to {value}')
super(SubPerson, SubPerson).name.__set__(self, value)
@name.deleter
def name(self):
print('Deleting name')
super(SubPerson, SubPerson).name.__delete__(self)

import time
class Date:
# Primary constructor
def __init__(self, year, month, day):
self.year = year
self.month = month
self.day = day
# Alternate constructor
@classmethod
def today(cls):
t = time.localtime() #它接收一個(gè)class作為第一個(gè)參數(shù)，它被用來創(chuàng)建并返回最終的實(shí)例， 這個(gè)cls==__init__
return cls(t.tm_year, t.tm_mon, t.tm_mday)

"""普通調(diào)用"""
c = Date(2010, 12, 12)

"""類方法在繼承中使用"""
class NewDate(Date):
pass
c = Date.today() # Creates an instance of Date (cls=Date)
d = NewDate.today() # Creates an instance of NewDate (cls=NewDate)

from abc import ABCMeta, abstractmethod
class IStream(metaclass=ABCMeta):
@abstractmethod
def read(self, max_bytes=-1):
pass
@abstractmethod
def write(self, data):
pass
"""不能被實(shí)例化"""
#a = IStream()

class SocketStream(IStream):
def read(self, max_bytes=-1):
pass
def write(self, data):
pass
"""檢查"""
def serialize(obj, stream):
if not isinstance(stream, IStream):
raise TypeError('Expected an IStream')
pass

from abc import ABCMeta, abstractmethod
class IStream(metaclass=ABCMeta):
@abstractmethod
def read(self, max_bytes=-1):
pass
@abstractmethod
def write(self, data):
pass
import io
# Register the built-in I/O classes as supporting our interface
IStream.register(io.IOBase)

# Open a normal file and type check
f = None #open('test.txt')
print(f'f object is IStream type: {isinstance(f, IStream)}')
#f object is IStream type: False

from functools import total_ordering
class Room:
def __init__(self, name, length, width):
self.name = name
self.length = length
self.width = width
self.square_feet = self.length * self.width
@total_ordering
class House:
def __init__(self, name, style):
self.name = name
self.style = style
self.rooms = list()
@property
def living_space_footage(self):
return sum(r.square_feet for r in self.rooms)
def add_room(self, room):
self.rooms.append(room)
def __str__(self):
return f'{self.name}: {self.living_space_footage} square foot {self.style}'
def __eq__(self, other):
return self.living_space_footage == other.living_space_footage

def __lt__(self, other):
return self.living_space_footage < other.living_space_footage
# Build a few houses, and add rooms to them
h1 = House('h1', 'Cape')
h1.add_room(Room('Master Bedroom', 14, 21))
h1.add_room(Room('Living Room', 18, 20))
h1.add_room(Room('Kitchen', 12, 16))
h1.add_room(Room('Office', 12, 12))

h2 = House('h2', 'Ranch')
h2.add_room(Room('Master Bedroom', 14, 21))
h2.add_room(Room('Living Room', 18, 20))
h2.add_room(Room('Kitchen', 12, 16))

h3 = House('h3', 'Split')
h3.add_room(Room('Master Bedroom', 14, 21))
h3.add_room(Room('Living Room', 18, 20))
h3.add_room(Room('Office', 12, 16))
h3.add_room(Room('Kitchen', 15, 17))
houses = [h1, h2, h3]

print(f'Is {h1} bigger than {h2}: {h1 > h2}')
print(f'Is {h2} smaller than {h3}: {h2 < h3}')
print(f'Is {h2} greater than or equal to {h1}: {h2 >= h1}')
print(f'Which one is biggest in houses: {max(houses)}')
print(f'Which is smallest in houses: {min(houses)}')

""""""
# Is h1: 990 square foot Cape bigger than h2: 846 square foot Ranch: True
# Is h2: 846 square foot Ranch smaller than h3: 1101 square foot Split: True
# Is h2: 846 square foot Ranch greater than or equal to h1: 990 square foot Cape: False
# Which one is biggest in houses: h3: 1101 square foot Split
# Which is smallest in houses: h2: 846 square foot Ranch
# """"""
class House:
def __eq__(self, other):
pass
def __lt__(self, other):
pass
# Methods created by @total_ordering
__le__ = lambda self, other: self < other or self == other
__gt__ = lambda self, other: not (self < other or self == other)
__ge__ = lambda self, other: not (self < other)
__ne__ = lambda self, other: not self == other