为什么 input() function 返回无？

Question

So I am using Jupyter notebook and when I run the code

name = input(print('What is your name?'))

The code will produce the output:

What is your name?

None []

Since I cant copy and paste the rectangle that comes when using the function input(), lets asume the brackets represent that rectangle. Then say you write John Doe in the box, it will then show NoneJohn Doe Why is the word None shown next to the name and the box? How do you remove it? Thanks

Answer 1

I believe you want to prompt the user to type his/her name and then print out the name? if so, try this:

name = input('What is your name?')
print('Your name is '+ name)

Also with this in mind. Input takes a prompt string as its argument, which it will print automatically, but print returns None; it is this that gets printed by input. Your code is equivalent to:

name = print(...) # prompt == None
ans = str(input(name))

Instead, use str.format to build the prompt and pass it straight to input