[None]* 在 python 中是什么意思

Question

I was recently studying someone's code and a portion of code given below

class Node:
def __init__(self, height=0, elem=None):
    self.elem = elem
    self.next = [None] * height

What does it mean by [None] * height in the above code

I know what does * operator (as multiplication and unpacking) and None means in python but this is somehow different.

Answer 1

It means a list of None s with a height number of elements. eg, for height = 3 , it is this list:

[None, None, None]

Answer 2

If you do -

[element] * 3

You get -

[element, element, element]

That's what the code does, [None] * height

That is, if -

height = 4
[None] * height 
# equals [None, None, None, None]

Answer 3

>>> [None]  * 5
[None, None, None, None, None]

Gives you a list of size height in your case