Python Data Model

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

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

from collections import namedtuple
from random import choice
#namedtuple用于构建没有方法且少量属性的对象，比较方便的适用于数据库存储的实体对象。
Card = namedtuple('Card', 'rank suit')

class Deck(object):
	'''自定义的对象，自己重写了__len__和__getitem__方法。'''
	ranks = [str(n) for n in range(2, 11)] + list('JQKA')
	suits = 'S D C H'.split()
	
	def __init__(self):
		self._cards = [Card(rank, suit) for suit in self.suits for rank in self.ranks]
	
	def __len__(self):
		'''查看有多少张牌'''
		return len(self._cards)
	
	def __getitem__(self, pos):
		'''为了实现deck[0],deck[2]模型，自动支持切片和可迭代对象'''
		return self._cards[pos]
	
# 为了排序用的
suit_values = dict(S = 3, D = 1, C = 0, H = 2)
def sorted_high(card):
	rank_value = Deck.ranks.index(card.rank)
	return rank_value + len(suit_values) + suit_values[card.suit]
	

if __name__ == "__main__":
	deck = Deck()
	print(len(deck), deck[0])
	a = choice(deck)
	print(a)
	#对于in操作，如果没有实现__contains__方法，in云算法会进行一次迭代搜索。
	print(Card('A', 'H') in deck)
	for i in sorted(deck, key= sorted_high):
		print(i)
#输出为
52 Card(rank='2', suit='S')
Card(rank='4', suit='C')
True
Card(rank='2', suit='C')
.
.
.
Card(rank='A', suit='S')

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

from math import hypot

class Vector(object):
	def __init__(self, x = 0, y = 0):
		self.x = x
		self.y = y
		
	def __repr__(self):
		return 'Vector(%r,%r)' % (self.x, self.y)
	
	def __abs__(self):
		'''实现vector的长度计算'''
		return hypot(self.x, self.y)
	
	def __bool__(self):
		'''默认情况下，自定义的类实例都是True，除非自己实现该函数。调用bool(x),x首先调用__bool__方法，如果不存在则去调用__len__方法。'''
		return bool(abs(self))
	
	def __add__(self, other):
		'''实现vector1+vector2的加法操作'''
		x = self.x + other.x
		y = self.y + other.y
		return Vector(x, y)
	
	def __mul__(self, scalar):
		'''实现vector1x10的加法操作'''
		return Vector(self.x * scalar, self.y * scalar)
		
if __name__ == "__main__":
	v1 = Vector(1, 2)
	v2 = Vector(1, 2)
	print(abs(v1))
	print(v1 + v2)
	print(v1 * 10)
#输出为
2.23606797749979
Vector(2,4)
Vector(10,20)