# 簡單的購物小程序product_list = [  ['surface pro 4', 7800],  ['dell xps 15', 12000],  ['macbook', 12000],  ['小米6', 2499],  ['iphone7', 4600],  ['堅(jiān)果Pro', 1499]]shopping_list = []# 判斷輸入的薪水格式是否正確while True:  salary = input('/n請輸入您的薪水：')  if not salary.isdigit():          # 薪水不是數(shù)字，結(jié)束循環(huán)    print('/n輸入格式有誤！請重新輸入...')    continue  breakbalance = salary = int(salary)print('/n-----------歡迎購買------------/n')# 生成帶序號(hào)的商品列表for index, item in enumerate(product_list):  print(index, item)# 判斷輸入的序號(hào)是否符合要求while True:  while True:    i = input('/n輸入您要購買的商品序號(hào)，或輸入 q 取消購買：')    if i == 'q':                 # 輸入 q 退出購買界面      while True:        a = input('/n是否繼續(xù)購買？(Y/N)：')        if a != 'n' and a != 'N' and a != 'y' and a != 'Y':          print('/n輸入格式有誤，請重試...')          continue        elif a == 'y' or a == 'Y':         # 繼續(xù)購買          break        else:                    # 購買完畢          if balance == salary:       # 沒有買任何東西            print('/n交易結(jié)束，購買失敗...')            exit()          else:               # 結(jié)算              print('/n您已成功購買以下商品：/n')            for item in shopping_list:              print(item)            print('/n共消費(fèi)金額 %d 元，余額 %d 元' % (salary - balance, balance))            exit()      continue    if not i.isdigit():             # 序號(hào)不是數(shù)字，結(jié)束循環(huán)      print('/n輸入格式有誤！請重新輸入...')      continue    i = int(i)    if i < 0 or i >= len(product_list):  # 序號(hào)范圍不正確，結(jié)束循環(huán)      print('/n此商品不存在，請重新輸入...')      continue    break  product = product_list[i]  price = int(product[1])  # 判斷余額是否充足，夠就直接扣款，不夠提醒  if price <= balance:    balance -= price    shopping_list.append(product_list[i])    print('/n您已成功購買 %s ，當(dāng)前余額為 %d 元' %(product, balance))  else:    print('/n購買失敗，您的余額不足...')  while True:    a = input('/n是否繼續(xù)購買？(Y/N)：')    if a != 'n' and a != 'N' and a != 'y' and a != 'Y':      print('/n輸入格式有誤，請重試...')      continue    break  if a == 'Y' or a == 'y':    continue  else:    breakif balance == salary:  print('/n交易結(jié)束，購買失敗...')  exit()else:  print('/n您已成功購買以下商品：/n')  for item in shopping_list:    print(item)  print('/n共消費(fèi)金額 %d 元，余額 %d 元' %(salary-balance, balance))  exit()