#!/usr/bin/env python3

# -*- coding: utf-8 -*-

"""

Created on Mon Apr 20 21:08:08 2020

@author: root

"""

import collections

Card = collections.namedtuple('Card', ['rank','suit'])

class FrenchDeck:

     ranks = [str(n) for n in range(2,11)]+list('JQKA')

     suits='spades diamods clubs hearts'.split()

     def __init__(self):

         self._cards= [Card ('rank','suit') for suit in self.suits

                                            for rank in self.ranks]

     def __len__(self):

         return len(self._cards)

     def __getitem__(self,position):

         return self._cards[position]

beer_card = Card('7','diamods')

print ('beer_card',beer_card)

deck=FrenchDeck()

print (len(deck))

# example1

from random import choice

choice(deck)

print (choice(deck))

#__getitem__

for card in deck:

    print(card)

for card in reversed(deck):

    print (card)

Card('Q','hearts') in deck 

suit_values=dict(spades=3,hearts=2,diamonds=1,clubs=0)

def spades_high(card):

    rank_value = FrenchDeck.ranks.index(card.rank)

    return rank_value*len(suit_values)+suit_values[card.suit]

for card in sorted(deck,key=spades_high):

    print (card)

"""

Python的魔法方法__getitem__ 可以让对象实现迭代功能，

这样就可以使用for...in... 来迭代该对象了

在用 for..in.. 迭代对象时，如果对象没有实现

 __iter__ __next__ 迭代器协议，

 Python的解释器就会去寻找__getitem__ 来迭代对象

 ，如果连__getitem__ 都没有定义，这解释器就会报对象不是迭代器的错误：

"""

class Animals:

    def __init__(self,animal_list):

        self.animals_name=animal_list

    def __getitem__(self,index):

        return self.animals_name[index]

animals=Animals(['dog','cat','fish'])

for animal in animals:

    print (animals)

#!/usr/bin/env python3

# -*- coding: utf-8 -*-

"""

Created on Mon Apr 20 22:39:15 2020

@author: root

"""

from math import hypot

class Vector:

    def __init__(self,x=0,y=0):

        self.x=x

        self.y=y

    def __repr__(self):

        return 'repr vector(%r,%r)'%(self.x,self.y)

    def __abs__(self):

        return hypot(self.x,self.y)

    def __bool__(self):

        return bool(abs(self))

    def __add__(self,other):

        x=self.x + other.x

        y=self.y + other.y

        return Vector(x,y)

    def __mul__(self,scalar):

        return Vector(self.x*scalar,self.y*scalar)

a=Vector(1,2)

b=Vector(3,4)

print (a+b)