Check if string is None, empty or has spaces only

Question

What's the Pythonic way of checking whether a string is None, empty or has only whitespace (tabs, spaces, etc)? Right now I'm using the following bool check:

s is None or not s.strip()

..but was wondering if there's a more elegant / Pythonic way to perform the same check. It may seem easy but the following are the different issues I found with this:

isspace() returns False if the string is empty.
A bool of string that has spaces is True in Python.
We cannot call any method, such as isspace() or strip(), on a None object.

That looks reasonable, though perhaps you could think about ways to exclude `None` by other means earlier in the code. — tripleee, Jul 19 '22 at 13:25
Thinking about it the opposite way: `if s and s.strip(): do_something_with_s()` — Tomerikoo, Jul 19 '22 at 13:28

Tomerikoo · Answer 1 · 2022-07-19T13:42:28.293

4

The only difference I can see is doing:

not s or not s.strip()

This has a little benefit over your original way that not s will short-circuit for both None and an empty string. Then not s.strip() will finish off for only spaces.

Your s is None will only short-circuit for None obviously and then not s.strip() will check for empty or only spaces.

edited Jul 19 '22 at 13:42

answered Jul 19 '22 at 13:37

Tomerikoo

18,379
16
47
61

One possible improvement could be doing `set(s)!={" "}` instead of `not s.strip()`, but that's getting a bit bikesheddy – 0x263A Jul 19 '22 at 13:48

Check if string is None, empty or has spaces only

1 Answers1