Return true if list is not empty

Question

What is the most pythonic way to return true if a list is not empty?

def fun(x):
    return x != []

Given some function called fun where we pass in a list x. List could look like [] or [1,3,4].

I want to return True if the list is not empty. Am I doing that in the most pythonic way?

The reason I ask is because when I do return x is not None instead of return x != [] I get a different answer. I guess this is because empty list is not considered null?

[bool](https://docs.python.org/3/library/functions.html#bool) — dawg, Aug 25 '20 at 16:03
Just cast the list to bool. bool([1,2,3]) = True. bool([]) = False. Because you want True if empty, then do: not(bool(x)). — Alan, Aug 25 '20 at 16:04
Either `bool(x)`, or just `x`. In most cases, you don't need an actual Boolean value. — Carcigenicate, Aug 25 '20 at 16:04
*"empty list is not considered null"* - an empty list, or any list, `is not None`, no. The ideal implementation here will depend partly on what you expect to happen if `x` *isn't* a list. — jonrsharpe, Aug 25 '20 at 16:04

creed · Accepted Answer · 2020-08-25T16:16:45.060

1

You can check the length of the list to see how many items are inside:

def fun(x):
    return len(x) > 0

Or you can cast bool to be more pythonic:

def fun(x):
    return bool(x)

edited Aug 25 '20 at 16:16

answered Aug 25 '20 at 16:07

creed

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Return true if list is not empty

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