为什么函数的返回值是用Python打印的？

Question

这是python的新手,试试这个 -

def newlines():
    print()
    print()
    print()    
question = "Which online Course you have signed up, dude?"
response = "Good Luck to you, dude!"
print(question), newlines(), input(), newlines(), print(response)

在Python 3.2.*中输出就是这个

Which online Course you have signed up, dude?



Nothing



Good Luck to you, dude!

(None, None, "Nothing", None) # Where this output is coming from ?

python 3.3 beta也没有发生这种情况

Answer 1

您必须在交互式shell中.当我将代码作为文件运行时,我得到了这个输出:

$ python3.2 test.py
Which online Course you have signed up, dude?



dlkjdf



Good Luck to you, dude!
$

您只能在控制台获得输出:

>>> def newlines():
...     print()
...     print()
...     print()    
... 
>>> question = "Which online Course you have signed up, dude?"
>>> response = "Good Luck to you, dude!"
>>> 
>>> print(question), newlines(), input(), newlines(), print(response)
Which online Course you have signed up, dude?



dljdldk



Good Luck to you, dude!
(None, None, 'dljdldk', None, None)
>>> 

这是因为控制台将打印您输入的最后一个内容的表示.最后一个语句实际上是一个元组,因此它最后会打印出来.以下是一些例子:

>>> 3
3
>>> 4
4
>>> 3, 4, None, "hey"
(3, 4, None, 'hey')