03 of learning python

01 input输入的是str类型

如果输入的是数字的话，要记得强制转换一下！

02 isdigit()

这个方法是用来检测字符串是否全部由数字组成

str.isdigit()

如果字符串只包含数字则返回 True 否则返回 False。

03 购物车程序

 '''程序：购物车程序
 需求:
 启动程序后，让用户输入工资，然后打印商品列表
 允许用户根据商品编号购买商品
 用户选择商品后，检测余额是否够，够就直接扣款，不够就提醒
 可随时退出，退出时，打印已购买商品和余额'''
 # -*- coding: utf-8 -*-
 print("-------shopping_cart-------")
 print("There is the goods and its price:")
 flag = [1, 2, 3, 4, 5]
 GoodsList = ["A", "B", "C", "D", "E"]
 value = [50, 100, 150, 200, 250]//这里把这俩列表嵌套会更好一些！！
 for i in flag:
     a = GoodsList[i - 1]
     b = value[i - 1]
     print(str(i) + ". " + a + ", " + str(b))
 Salary = input("please input your salary:")
 LeftSalary = int(Salary)
 AlreadyBuy = []
 while True:
     Number = input("please input your choice(input the number):")
     if Number.isdigit() and int(Number) in range(1, 6):
         if LeftSalary < value[int(Number) - 1]:
             print("sorry, your money isn't enough")
         else:
             AlreadyBuy.append(GoodsList[int(Number) - 1])
             LeftSalary = LeftSalary - value[int(Number) - 1]
             print("you have %d left" % LeftSalary)
     elif Number == "quit":
         print("you have end the process,you have %d left" % LeftSalary)
         print("you have bought:", AlreadyBuy)
         break
     else:
         print("you have input the wrong commend!")