'''
        面向物件高階程式設計
'''
from enum import Enum

'''
    __slots__
        限制例項屬性
        定義的屬性只對當前類例項起作用,對於繼承的子類不起作用

'''
class Student(object):
    __slots__ = ('name', 'age')
s = Student()#建立一個新的例項
s.name = '張三'#繫結屬性
s.age = 45
#s.score = 99,在__slots__中沒有score則不不能繫結
print(s.name)

'''
    @propert
'''
 


class Student(object):

    @property
    def score(self):
        return self._score

    @score.setter
    def score(self, value):
        if not isinstance(value, int):
            raise ValueError('score must be an integer!')
        if value < 0 or value > 200:
            raise ValueError('score must between 0 ~ 200'
 
)
        self._score = value
s = Student()
s.score = 60#實際轉化為s.set_score(60)
print(s.score)#例項轉化為s.get_score()

'''
    多重繼承
        Python允許使用多重繼承
'''

'''
    定製類
        __str__

'''

'''
    __str__
    __repr__ 同上
    __iter__

'''

class Student(object):

    def __init__(self, name):
        self.name = name

print(Student('張三'
 
))##預設列印方式

class Student(object):
    def __init__(self, name):
        self.name = name

    def __str__(self):
        return 'Student object (name: %s)' % self.name

    __pepr__ = __str__

print(Student('張三'))##複寫__str__方法列印方式

'''
    __iter__
        類似於想被for...in迴圈,必須實現一個__iter__()方法改方法返回一個迭代物件,然後
        Python的for迴圈不斷呼叫改迭代對昂的__next__()方法迴圈到下一個值,知道遇到StopIteration錯誤退出迴圈
'''
class Fib(object):

    def __init__(self):
        self.a, self.b = 0, 1#初始化兩個計數器a,b

    def __iter__(self):
        return self#例項本省就是迭代物件,故返回自己

    def __next__(self):
        self.a, self.b = self.b, self.a + self.b #計算下一個值
        if self.a > 100000:#退出迴圈條件
            raise StopIteration()
        return self.a#返回下一個值

    def __getitem__(self, item):#想像list中一樣取出下標 必須實現__getitem__()方法
        a, b = 1, 1
        for x in range(item):
            a, b = b, a + b
        return a

for n in Fib():
    print(n)

'''
    __getitem__
        想像list中一樣取出下標 必須實現__getitem__()方法
'''
class Fib(object):

    def __init__(self):
        self.a, self.b = 0, 1#初始化兩個計數器a,b

    def __iter__(self):
        return self#例項本省就是迭代物件,故返回自己

    def __next__(self):
        self.a, self.b = self.b, self.a + self.b #計算下一個值
        if self.a > 100000:#退出迴圈條件
            raise StopIteration()
        return self.a#返回下一個值

    def __getitem__(self, item):#想像list中一樣取出下標 必須實現__getitem__()方法
        a, b = 1, 1
        for x in range(item):
            a, b = b, a + b
        return a

f = Fib()
print(f[9])

'''
    __getattr__
        正常情況下,當我們呼叫類的方法或屬性時,如果不存在,就會報錯。
'''

class Student(object):
    def __init__(self):
        self.naame = "張三"

    def __getattr__(self, item):#不存在時會返回99
        if item == 'score':
            return 99
s  = Student()
print(s.name)
print(s.score)

'''
    __call__
        例項本身呼叫屬性和方法
'''

class Student(object):
    def __init__(self, name):
        self.name = name

    def __call__(self):
        print('My name is %s.' % self.name)
s = Student("張三")
print(s())

'''
    使用列舉類
'''
from enum import Enum

Month = Enum('Moth', ('Jan', 'Fen', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'))

for name, member in Month.__members__.items():
     print(name, '=>', member, ',', member.value)

print(Month.Mar.value)

from enum import Enum, unique

@unique
class Weekday(Enum):
    Sun = 0#Sun的value被設定為0
    Mon = 1
    Tue = 2
    Web = 3
    Thu = 4
    Fri = 5
    Sat = 6
print(Weekday.Mon)
print(Weekday.Thu)
print(Weekday['Tue'])
print(Weekday(5))

'''
    使用元類

'''

'''
    type
        動態語言和靜態語言的最大不同,就是函式和類的定義,不是編譯時定義的,而是執行時動態建立的

'''

class Hello(object):
    def hello(self, name = 'world'):
        print('Hello, %s.' % name)

h = Hello()
print(h.hello())
print(type(Hello))
print(type(h))

def fn(self, name = 'world'):#先定義函式
    print('Hello, %s.' % name)
#建立一個class物件, type()函式一次傳入3個引數
#1class名稱
#2繼承的父類集合,注意Python支援多重繼承,如果只有一個父類,別忘了tuple的單元寫法,後面跟個','號
#3class的方法名稱與函式繫結,這裡我們把函式fn繫結到方法名為hello上.
Hello = type('Hello', (object,), dict(hello=fn))
h = Hello()
print(h.hello())

'''
    metaclass
'''
class ListMetaclass(type):
    #接收引數
    #1當前準備建立的類的物件
    #2類的名字
    #3累積繼承的集合
    #4類的方法集合
    def __new__(cls, name, bases, attrs):
        attrs['add'] = lambda self, value: self.append(value)
        return type.__new__(cls, name, bases, attrs)
class MyList(list, metaclass=ListMetaclass):
    pass

L = MyList()
L.add(1)
print(L)

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