2019.5.16 课后练习。简易购物车程序

根据之前看过的知识点，以自己的思路先写出了一个程序，后续继续老师的操作再进行优化。

salary = int(input("请输入您的工资（单位 元）:"))

print("以下是可购清单：")

shopping_list = ['','iphone','computer','book','apple_juice','bread','cake']#商品列表
commodity_prices = [0,6000,7000,2,3,3,5] #商品价格列表
already_buy = []#已经购买的商品列表

print("1.",shopping_list[1],commodity_prices[1],"元")
print("2.",shopping_list[2],commodity_prices[2],"元")
print("3.",shopping_list[3],commodity_prices[3],"元")
print("4.",shopping_list[4],commodity_prices[4],"元")
print("5.",shopping_list[5],commodity_prices[5],"元")
print("6.",shopping_list[6],commodity_prices[6],"元")

select = ""
while select != "quit":
    select = input("购买您需要的宝贝至购物车，请输入数字（如需结算，输入 quit）：")
    print()
    if select == "1":
        salary = salary - commodity_prices[1]
        if salary < 0:
            print("余额不足，",salary)
            salary = salary + commodity_prices[1]
        else:
            print("已加入",shopping_list[1],"到你的购物车，当前余额：",salary)
        already_buy.append(shopping_list[1])
    elif select == "2":
        salary = salary - commodity_prices[2]
        if salary < 0:
            print("余额不足，", salary)
            salary = salary + commodity_prices[2]
        else:
            print("已加入", shopping_list[2], "到你的购物车，当前余额：", salary)
        already_buy.append(shopping_list[2])
    elif select == "3":
        salary = salary - commodity_prices[3]
        if salary < 0:
            print("余额不足，", salary)
            salary = salary + commodity_prices[3]
        else:
            print("已加入", shopping_list[3], "到你的购物车，当前余额：", salary)
        already_buy.append(shopping_list[3])
    elif select == "4":
        salary = salary - commodity_prices[4]
        if salary < 0:
            print("余额不足，", salary)
            salary = salary + commodity_prices[4]
        else:
            print("已加入", shopping_list[4], "到你的购物车，当前余额：", salary)
        already_buy.append(shopping_list[4])
    elif select == "5":
        salary = salary - commodity_prices[5]
        if salary < 0:
            print("余额不足，", salary)
            salary = salary + commodity_prices[5]
        else:
            print("已加入", shopping_list[5], "到你的购物车，当前余额：", salary)
        already_buy.append(shopping_list[5])
    elif select == "6":
        salary = salary - commodity_prices[6]
        if salary < 0:
            print("余额不足，", salary)
            salary = salary + commodity_prices[6]
        else:
            print("已加入", shopping_list[6], "到你的购物车，当前余额：", salary)
        already_buy.append(shopping_list[6])
else:
    print("您已购买以下商品：")
    print(already_buy)
    print("余额为：",salary)
    print("谢谢惠顾，欢迎下次光临！")

2019.5.20 根据老师讲课的内容进行优化

知识点1：列表的值可以进行嵌套。 如 sale_list = [['iphone',6000],('book',500),500,'bike'] 列表里面的值可以是 列表、元组、数字、字符串等

知识点2：嵌套列表取值， sale_list[0][1] 返回值是:6000

知识点3：函数 enumerate(sale_list,1) 。 在列表“sale_list”前面自动打印序号，默认不写“1”就从“0”开始

知识点4：for sale,price,unit in sale_list:。  通过for循环，把列表中的值取出来。

知识点5：print("已购买%s,当前余额：%d" % (sale_list[select - 1][0], saving))。 定位符使用

知识点6：函数 len(product_list)。 算出列表的长度

# 商品列表
sale_list = [
    ['iphone',7000,"￥"],
    ['bike',600,"￥"],
    ['computer',8000,"￥"],
    ['pen',3,"￥"],
    ['book',2,"￥"],
    ['desk',500,"￥"]
]

# 已购商品列表
shopping_list = []

# 预存金额，让用户自己输入
saving = input("请输入您需要存储的金额：")
# 判断是否输入的为数字
if saving.isdigit():
    saving = int(saving)
else:
    print("请输入数字！！！")

# 用while实现用户一直购物
while True:

    # for number,list in enumerate(sale_list,1):  #展示商品列表,此老师方法展示不好看，自己想了另外一个表达方式
    #     print(number,"  ",list)
    number = 0
    for sale,price,unit in sale_list:
        number += 1
        print("商品代码:",number,"  ",sale,price,unit)

    select = input("请输入您要购买的商品代码（退出，按‘Q’）：")  #让用户选择购买的商品
    if select.isdigit():
        select = int(select)
        if saving >= sale_list[select - 1][1]:  #判断是否买得起
            shopping_list.append(sale_list[select - 1]) #将购买的商品加入已购清单
            saving -= sale_list[select - 1][1]  #算出余额
            print("已购买%s,当前余额：%d" % (sale_list[select - 1][0], saving))
        else:
            print("余额不足，还剩余额为：%d" % saving)
    elif select == "q" or select == "Q":    #结算清单
        print("--------------您购买的清单如下-----------------")
        for shopping,price,unit in shopping_list: #打印已购清单
            print(shopping,price,unit)
        print("------------------------------------------------")
        print("welcome to you again!!!")
        break
    else:
        print("输入有误，请重新正确输入")