python - 我的 python 脚本有什么问题？不打印变量

Question

学习 Python 教程。我创建了一个简单的脚本 (myFirstFunction)，它没有执行预期的操作。我期望一行输出只是两个变量相乘:

apples = raw_input("How many apples do you have?")
oranges = raw_input("How many oranges do you have?")

def myFirstFunction(apples, oranges):
    total_fruit = apples * oranges
    print total_fruit

脚本确实按预期要求输入，但没有打印出结果？

myName-MacBook:pythonhard me$ python ex19b.py
How many apples do you have?2
How many oranges do you have?2
myNames-MacBook:pythonhard me$ 

为什么不打印出4？

Answer 1

这里有两个问题:

1. 您永远不会调用 myFirstFunction。这可以通过将其放在脚本末尾来完成:

   myFirstFunction(apples, oranges)
   

2. raw_input总是返回一个字符串对象。因此，在 myFirstFunction 中将输入相乘之前，需要将输入转换为整数。您可以通过将它们放在 int 中来做到这一点:

   apples = int(raw_input("How many apples do you have?"))
   oranges = int(raw_input("How many oranges do you have?"))
   

---

这是您脚本的固定版本:

apples = int(raw_input("How many apples do you have?"))
oranges = int(raw_input("How many oranges do you have?"))

def myFirstFunction(apples, oranges):
    total_fruit = apples * oranges
    print total_fruit

myFirstFunction(apples, oranges)

演示:

How many apples do you have?2
How many oranges do you have?2
4