如何将字典中的一个值与一个数字相乘，得到一个实际值？

Question

store={'Rice':450,'Beans':200,'Egg':40,'Fish':250,'Spag':250}

bill=()
total=()

print('Welcome!!!we sell:',"\n",[store])

while True:
    a=input('What would you like to buy?=')
    b=input('how many of each product do you want?=')
    if a in store:
        bill=store[a]*b
        print('bill=',bill)
    elif a not in store:
        print('Sorry we don\'t have that')
    else:
        total=bill+total
print('Total=',total)

Answer 1

• 你的if/elif/else是不可能的，因为无论a是否在字典中，你都无法进入else，所以把它放在if中

• 我还添加了一种通过输入stop来停止循环的方法，如果没有，您将无法停止程序并打印最终的total

• 将b输入移动到if中，如果产品不可用，则无需询问数量

• 在b上添加了int()转换

store = {'Rice': 450, 'Beans': 200, 'Egg': 40, 'Fish': 250, 'Spag': 250}
print('Welcome!!!we sell:', "\n", store)
total, bill = 0, 0
while True:
    a = input('What would you like to buy? ("stop" to quit): ')
    print(">" + a + "<")  # For OP debug purpose only, to be removed
    if a == "stop":
        break

    if a in store:
        b = int(input('how many of each product do you want?='))
        bill = store[a] * b
        total += bill
        print(f"Total={total} (+{bill})")
    else:
        print('Sorry we don\'t have that')

print('Total=', total)