variable = None in Python? What does it mean?

Question

I am new to coding. I saw some code where variable = None, what does it mean? I can't find an answer anywhere online.

Thanks in advance!

Well what do you think it means...? – Dunno Nov 29 '13 at 20:58 — Dunno, Nov 29 '13 at 20:58
http://docs.python.org/2/library/constants.html#None – Matt Ball Nov 29 '13 at 20:58 — Matt Ball, Nov 29 '13 at 20:58
+1 since this came up before the duplicate question. – JustBeingHelpful Sep 30 '14 at 20:12 — JustBeingHelpful, Sep 30 '14 at 20:12

score 5 · Accepted Answer · answered Nov 29 '13 at 21:02

5

It sets a variable named variable to None (Python's version of a null/nonetype object).

See a demonstration below:

>>> variable = None
>>> type(variable)
<type 'NoneType'>
>>>

I really think you should read one of the many Python tutorials out there since this is a fundamental language concept. Here are some I found useful:

answered Nov 29 '13 at 21:02

Thanks for pointing me towards tutorials, but what is the difference between setting variable to 0 versus setting it to None? – verkter Nov 29 '13 at 21:13
@verkter - It depends on the program. You are right in saying that, in a lot of areas, the two can be used interchangeably (since each evaluate to `False`). However, there are some instances when you need a nonetype/null object and `0` will not suffice. An example is with the [`filter`](http://docs.python.org/2.7/library/functions.html#filter) built-in. – Nov 29 '13 at 21:18

score 0 · Answer 2 · answered Nov 29 '13 at 20:57

0

It assigns the value None to the variable variable. I recommend you read the tutorial; it will answer this question and many more.

answered Nov 29 '13 at 20:57

user2357112

2 Answers2