Question

我使用python 3.5中的初学者编码知识将其作为一个有趣的小练习。

def potato_quant(number):
    if number >= 5 and number < 100:
        print("You've got more than 5 potatoes. Making a big meal eh?")
    elif number >= 100 and number < 10000:
        print("You've got more than 100 potatoes! What do you need all those potatoes for?")
    elif number >= 10000 and number < 40000:
        print("You've got more than 10000! Nobody needs that many potatoes!")
    elif number >= 40000:
        print("You've got more than 40000 potatoes. wut.")
    elif number == 0:
        print("No potatoes eh?")
    elif number < 5:
        print("You've got less than five potatoes. A few potatoes go a long way.")
    else:
        return 0
 def potato_type(variety):
     if variety == "Red":
        print("You have chosen Red potatoes.")
     elif variety == "Sweet":
        print("You have chosen the tasty sweet potato.")
     elif variety == "Russet":
          print("You've got the tasty average joe potatoe!")
     else:
          print("Nice potato!")

print(potato_quant(15000) + potato_type("Sweet"))

代码的目标是输入两个值并根据我的选择获得两个字符串。但是，当我运行代码时，我收到错误：

TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'

我是一个非常初学者，所以无论我多看多少，我都看不出有什么不对劲。任何帮助都将非常受欢迎，主要是为了将来使用。

Answer 1

将print替换为return，您就可以了：

def potato_quant(number):
    if number >= 5 and number < 100:
        return("You've got more than 5 potatoes. Making a big meal eh?")
    elif number >= 100 and number < 10000:
        return("You've got more than 100 potatoes! What do you need all those potatoes for?")
    elif number >= 10000 and number < 40000:
        return("You've got more than 10000! Nobody needs that many potatoes!")
    elif number >= 40000:
        return("You've got more than 40000 potatoes. wut.")
    elif number == 0:
        return("No potatoes eh?")
    elif number < 5:
        return("You've got less than five potatoes. A few potatoes go a long way.")
    else:
        return '0'

def potato_type(variety):
    if variety == "Red":
        return("You have chosen Red potatoes.")
    elif variety == "Sweet":
        return("You have chosen the tasty sweet potato.")
    elif variety == "Russet":
        return("You've got the tasty average joe potatoe!")
    else:
        return("Nice potato!")

print(potato_quant(15000) + potato_type("Sweet"))

在print(potato_quant(15000) + potato_type("Sweet"))行中，您正在调用函数potato_quant＆amp; potato_type必须返回要打印的值。

由于您的函数有print而不是return，因此它们会返回None，并且+上的操作数None未定义。因此错误信息。

如果potato_quant返回0，则会提升TypeError: unsupported operand type(s) for +: 'int' and 'str'。因此，我将return 0替换为replace '0'以解决此问题。

Answer 2

由于potato_quant和potato_type已经进行了打印，因此您无需在print来电中拨打电话。

您收到的错误是因为除return之外的函数没有else声明，因此默认情况下它会返回None

你真正需要做的就是改变最后一行：

print(potato_quant(15000) + potato_type("Sweet"))

到

potato_quant(1500)
potato_type("Sweet")

TypeError：+不支持的操作数类型：'NoneType'和'NoneType'

2 个答案: