Empty values in a Python list

Question

Is it possible to assign a list with empty values in Python?
This is possible:

x = []

But I want to do something like:

x = [4,7,2, ,8,9,1]

with an empty value inside. The reason is that I have a large number of lists with 7 values and sometimes one of the values are unavailable. I need to keep say 8 as x[4],9 as x[5] etc.

My thoughts:
Maybe I should just put a number like 999 inside, or a string "empty" and tell my code to ignore 999 or "empty" or whatever.

What is the best option here?

Answer 1

Use None for the "empty" value.

a = [1,2,3,4,5]
b = [11,22,None,44,55]

Answer 2

Another option other than using None is to use some other unique object such as empty = object() as this allows None to be used as a list item and then test if the list item is empty via l[x] is empty.

Answer 3

Use "None". It indicates that there is no value.