程式：購物車程式

需求:

    啟動程式後，讓使用者輸入工資，然後列印商品列表
    允許使用者根據商品編號購買商品
    使用者選擇商品後，檢測餘額是否夠，夠就直接扣款，不夠就提醒
    可隨時退出，退出時，列印已購買商品和餘額'''
shopping_list = []
shopping_goods = [
    ("bicycle",500),
    ("car",5000),
    ("computer",8000),
    ("liwei",88),
    ("liqui",66),
    ("xiaojun",664),
                  ]
salary = input("請輸入您的工資：")
if salary.isdigit():
    salary = int(salary)
    while True:
        for i in shopping_goods:
            print(shopping_goods.index(i),i)
        chouse = input("請選擇您需要的商品編號：")
        if chouse.isdigit():
            chouse = int(chouse)
            if chouse >= 0 and chouse < len(shopping_goods):
                p_itme = shopping_goods[chouse]
                if p_itme[1]<=salary:     #餘額足夠買得起商品
                    salary -= p_itme[1]
                    shopping_list.append(p_itme)
                    print("您已購買的商品為：%s"%shopping_list,"您的餘額還剩下:%s"%salary)
                else:
                    print("您的餘額不足")
                    print("您已經買的商品為:",shopping_list)
                    break
            else:
                print("您選擇的商品不存在，請從新選擇。")
        else:
            chouse == "eeeeeee"
            print("您所購買的商品為:", shopping_list,)
            print("您的餘額還剩下：%s"%salary)
            break