python每日一题：利用字典实现超市购物程序

购物车程序：
需求：

1. 启动程序，让用户输入工资，然后打印商品列表；

2.允许用户根据商品编号或者商品名字购买商品；

3.用户输入商品列表后检测余额是否足够，够就直接扣款，不够就提醒；

4.用户可以一直购买商品，也可以直接退出，退出后打印已购买商品和余额；

• balance=0
  shoplist=[{'identifier':1,'apple':5},{'identifier':2,'banana':4},{'identifier':3,'cake':20},{'identifier':4,'shoe':99},{'identifier':5,'diamond':200}]
  shoplist1,shoplist2,shoplist3=[],[],[]
  shop_cart={}
  for i in shoplist:
      k=i
      del k['identifier']
      shoplist1.append(k)#提取出商品名称和单价
      shoplist2.append(list(k.keys())[0])#单独提取出商品名称
      shoplist3.append(list(k.values())[0])#单独提取出商品单价
  salary=int(input('please input your salary:'))
  print("the selective menu are as follwed:")
  print(shoplist)
  print('please select your want goods:')
  while 1:
      want=input()    #可以输入商品的数字编号或者商品名字
      if  want.isdigit() and int(want) in range(1,len(shoplist)+1):
          want=int(want)
          goods=shoplist2[want - 1]
          price=shoplist3[want - 1]
      elif  want in shoplist2:
          p = shoplist2.index(want)
          goods=want
          price=shoplist3[p]
      else:
          print("the goods is not existed, please input again")
          continue
      print('you has selected:',goods, ',its price:', price)
      quantity = int(input('please input the quantity of the goods:'))
      if salary>=quantity*price:
          salary-=quantity*price
          balance+=quantity*price
          shop_cart[goods]={price:quantity}
      else:
          print('sorry,you can not afford it')
      print("you can input any word to keep shopping or input 'N'to end shopping")
      s=input()
      if s!='N':
          continue
      else:
          break
  print('your shoppinglist is as follows:')
  print(shop_cart)
  print('your shopping consuption is:',balance)

  编译结果如下：

  your shoppinglist is as follows:
  {'diamond': {200: 10}, 'apple': {5: 10}}
  your shopping consuption is: 2050