11 编码及购物车简单程序

#编码方式转换

print(bytes('你好',encoding='GBK'))                #unicode转换成'GBK' bytes
#b'\xc4\xe3\xba\xc3'
print(bytes('你好',encoding='GBK').decode('GBK'))  #再转换成unicode
#你好

print(bytes('你好',encoding='utf-8'))               #unicode转换成'utf-8' bytes
#b'\xe4\xbd\xa0\xe5\xa5\xbd'
print(bytes('你好',encoding='utf-8').decode('utf-8')) #'utf-8'转换成unicode
#你好

#encode 编码，如何将Unicode  str-->bytes

s1 = 'alex'
s11 = s1.encode('utf-8')
print(s11)      #b'alex'
s11 = s1.encode('gbk')
print(s11)      #b'alex'

s2 = '中国'
s22 = s2.encode('utf-8')
print(s22)      #b'\xe4\xb8\xad\xe5\x9b\xbd'
s22 = s2.encode('gbk')
print(s22)      #b'\xd6\xd0\xb9\xfa'

#购物车程序

li = [                              #商品列表
    {'name':'苹果','price':10},
    {'name':'香蕉','price':20},
    {'name':'西瓜','price':30},
    ]
print('欢迎光临本店')
shopping_car = {}       #购物车
money = input('让我看看你的钱：')
flag = True
if money.isdigit() and int(money)>0:        #输入的为数字且大于0
    while flag:
        for i,k in enumerate(li):       #枚举
            print('序号: {},  商品: {},  价格: {}'.format(i,k['name'],k['price']))
        choose = input('请输入您要购买的商品序号：')
        if choose.isdigit() and int(choose) < len(li):      #序号为数字且在列表内
            num = input('请输入您要购买的数量：')
            if num.isdigit():       #输入的数量为数字
                if int(money) >= li[int(choose)]['price']*int(num):  #现金>=单价*数量
                    money = int(money) - li[int(choose)]['price']*int(num) #金额 = 金额-单价*数量
                    if li[int(choose)]['name'] in shopping_car:  #序号在购物车内
                        shopping_car[li[int(choose)]['name']] = shopping_car[li[int(choose)]['name']] + int(num) #购物车数量=购物车数量+购买数量
                    else:
                        shopping_car[li[int(choose)]['name']] = int(num)    #购物车数量赋值
                        print('购物车中的商品有 {},您的余额为{}'.format(shopping_car,money))
                else:
                    print('你的资金不足！不能购买')
                    break
        else:
            print('你输入了为存在的序号')
else:
    print('你的钱不合法，不能购买商品！')