[Python-Dev] PEP 572 and assert (original) (raw)
Barry Warsaw barry at python.org
Tue Jul 17 15:58:42 EDT 2018
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On Jul 17, 2018, at 12:18, MRAB <python at mrabarnett.plus.com> wrote:
Why use len(...) == 0 instead of not(...)?
assert not(subdirs := list(path.iterdir())), subdirs
Off-topic, but it’s a style thing. Some style guides (and my personal preference) require to be more explicit when checking for empty sequences. I’ll use a boolean test (e.g. not or false-iness) when the subject could be empty, None, or the empty string, and len() == 0 when the subject is supposed to be a sequence.
-Barry
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