198
Python Performance: Why 'if not list' is 2x Faster Than Using len()
(blog.codingconfessions.com)
this post was submitted on 12 Apr 2025
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I don't know, it throws me off but perhaps because I always use len in this context. Is there any generally applicable practical reason why one would prefer "not" over len? Is it just compactness and being pythonic?
I feel like that only serves the purpose up to the point that methods are not over reaching otherwise then it turns into remembering what a method does for a bunch of unrelated objects.
lenalso works on a dict.The point stands. If you want to check if a value is "empty," use the check for whether it's "empty." In Python, that's
not. If you care about different types of empty (e.g.Nonevs[]vs{}), then make those checks explicit. That reads a lot better than doing an explicit check where the more common "empty" check would be correct, and it also make it a lot more obvious when you're doing something special.