Python - Get number of items in list not equal to something

Question

How do you get the number of items that are NOT 204 in this list?

data = [204, 204, 204, 500, 204, 204, 500, 500, 204, 404]

number_of_not_204 = any(x != 204 for x in data)

# returns True
print number_of_not_204

# looking to get the number 4 (500, 500, 500, and 404 are not 204)

Or without numpy: `countNot204 = len(data)-data.count(204)` – Alain T. May 24 '19 at 22:46 — Alain T., May 24 '19 at 22:46

score 6 · Answer 1 · answered May 24 '19 at 18:44

6

You are describing the basic usage of built-in function sum:

>>> data = [204, 204, 204, 500, 204, 204, 500, 500, 204, 404] 
>>> sum(1 for n in data if n != 204) 
4

answered May 24 '19 at 18:44

wim

338,267
99
616
750

I know you know, but can be more simplified (as shown in my answer). :) – Austin May 24 '19 at 18:46
1

I know. That's shorter, but less readable imo. – wim May 24 '19 at 18:46

score 4 · Answer 2 · answered May 24 '19 at 18:45

4

Use sum() on generator:

number_of_not_204 = sum(x != 204 for x in data)

answered May 24 '19 at 18:45

Austin

25,759
4
25
48

score 1 · Answer 3 · answered May 24 '19 at 18:46

1

You can use len() on new list without 204:

data = [204, 204, 204, 500, 204, 204, 500, 500, 204, 404]
x = len([i for i in data if i != 204])

answered May 24 '19 at 18:46

Olvin Roght

7,677
2
16
35

it's a waste to generate the whole list only to calculate its length. – cs95 May 24 '19 at 18:54
@cs95, of course, I've not said that it's the best. For me it's just most obvious. – Olvin Roght May 24 '19 at 21:48

Python - Get number of items in list not equal to something

3 Answers3