I often find myself defining function args with list[SomeClass] type and think “do I really care that it’s a list? No, tuple or Generator is fine, too”. I then tend to use Iterable[SomeClass] or Collection[SomeClass]. But when it comes to str, I really don’t like that solution, because if you have this function:

def foo(bar: Collection[str]) -> None:
    pass

Then calling foo("hello") is fine, too, because “hello” is a collection of strings with length 1, which would not be fine if I just used list[str] in the first place. What would you do in a situation like this?

  • pythonoob
    1·
    10 months ago

    I’m not sure why you wouldn’t just use packing to pass in a list of some objects that you need iterate over? Isn’t it normally bad form to pass lists as arguments? I feel like I’ve read this somewhere but can’t cite it