[Python-Dev] PEP 0424: A method for exposing a length hint (original) (raw)

Steven D'Aprano steve at pearwood.info
Sun Jul 15 18:39:01 CEST 2012

Steven D'Aprano wrote:

With a length hint, we could strengthen that promise:

"if lengthhint returns a negative number, list, tuple and set will fail immediately with MemoryError" which I think is a good safety feature for some things which cannot possibly succeed, but risk DOSing your system. Does it prevent every possible failure mode? No, of course not. But just because you can't prevent every problem doesn't mean you should prevent the ones which you can.

Gah, I messed that last sentence up. It should read:

just because you can't prevent every problem doesn't mean you SHOULDN'T prevent the ones which you can.

-- Steven

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