Question

我正在做一些功课，在下面的代码选项中，有四个遇到错误（Python 3.5）。

不能将序列乘以非int类型＆＃39; float＆＃39;

def main():
    costpp = 20.00
    numberOfPeople = input("How many people are coming to wedding?")
    print("Please select a number for your choice:")
    print("1) Print the invitee list")
    print("2) Print the menu")
    print("3) Print the text of the invitation")
    print("4) Print your cost")
    choice = input()
    if choice == "1":
        printInviteeList()
    if choice == "2":
        printMenu()
    if choice == "3":
        print("You are invited to the wedding")
    if choice == "4":
        printCost  (numberOfPeople,   costpp)

def printInviteeList(): 
    print("Mia, Olga,   Sahar,    Rcheal, Ding, Gary, Jenny,    Lian,    Quan, Jack")

def printMenu():
    print("Beef, Lamb, Bread, Egg, Crab, Cake")

def printCost(numberOfPeople, costPerPerson):       
    totalcost = numberOfPeople*costPerPerson
    return totalcost

main()

Answer 1

input()返回一个字符串，所以在这一行之后：

numberOfPeople = input("How many people are coming to wedding?")

numberOfPeople将是一个字符串。假设您输入了100，numberOfPeople将成为字符串'100'。

将字符串乘以浮点数无效 - 这没有意义：

>>> numberOfPeople * 2.0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can't multiply sequence by non-int of type 'float'

要解决此问题，请将numberOfPeople转换为数字类型，在这种情况下使用int转换为int()：

numberOfPeople = int(input("How many people are coming to wedding?"))

>>> numberOfPeople * 2.0
200.0

值得注意的是，将字符串乘以int：

是有效的

>>> '100' * 2
'100100'

连接字符串 n 次，在本例中为2。

不能将序列乘以非整数类型＆＃39; float＆＃39;对于某些输入

1 个答案: