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John Carmack on mutable variables

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498 points azhenley | 1 comments | 31 Oct 25 02:34 UTC | HN request time: 0.001s | source
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sgarland ◴[31 Oct 25 10:47 UTC] No.45770550[source]▶
Dumb question from a primarily Python programmer who mostly writes (sometimes lengthy) scripts: if you have a function doing multiple API calls - say, to different AWS endpoints with boto3 - would you be expected to have a different variable for each response? Or do you delete the variable after it’s handled, so the next one is “new?”
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TZubiri ◴[31 Oct 25 10:54 UTC] No.45770602[source]▶
I think renaming an old variable is a common and sensible way to free a resource in python. If there are no valid names for a resource it will be garbage collected. Which is different in languages like C++ with manual memory management.

John Carmack is a C++ programmer apparently that still has a lot to learn in python.

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1. maleldil ◴[31 Oct 25 16:02 UTC] No.45773607[source]▶
Not "a resource", but memory specifically. If there's a proper resource (e.g. a file), you should ensure it's explicitly released instead of relying on the GC (using with/close/etc.) And if memory usage is really important, you should probably explicitly delete the variable.

Anything else is wishful thinking, trying to rely on the GC for deterministic behaviour.