195
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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Technology
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if you're worried about readability you can leave a comment.
Comments shouldn't explain code. Code should explain code by being readable.
Comments are for whys. Why is the code doing the things it's doing. Why is the code doing this strange thing here. Why does a thing need to be in this order. Why do I need to store this value here.
Stuff like that.
There is no guarantee that the comment is kept up to date with the code. "Self documenting code" is a meme, but clearly written code is pretty much always preferable to unclear code with a comment, largely because you can actually be sure that the code does what it says it does.
Note: You still need to comment your code kids.
Better yet, a type hint.
foo: list | Nonecan be checked by static analysis,# foo is a listisn't.If there is an alternative through which I can achieve the same intended effect and is a bit more safer (because it will verify that it has len implemented) I would prefer that to commenting. Also if I have to comment every len use of not that sounds quite redundant as len checks are very common