Python 3.3 TypeError:+不支持的操作数类型:'NoneType'和'str'

Question

编程新手并不确定我为什么会收到此错误

count=int(input ("How many donuts do you have?"))
if count <= 10:
    print ("number of donuts: " ) +str(count)
else:
    print ("Number of donuts: many")

Answer 1

在python3中,print是一个返回的函数None.所以,行:

print ("number of donuts: " ) +str(count)

你有None + str(count).

你可能想要的是使用字符串格式:

print ("Number of donuts: {}".format(count))

Answer 2

您的括号位于错误的位置:

print ("number of donuts: " ) +str(count)
                            ^

把它移到这里:

print ("number of donuts: " + str(count))
                                        ^

或者只使用逗号:

print("number of donuts:", count)