[issue39178] Should we make dict not accept a sequence of sets?

[Steven D'Aprano]

Steven D'Aprano <steve+python at pearwood.info> added the comment:

"should dict preemptively make sure it doesn't accept a sequence of sets"

No. The person on StackOverflow made a mistake in their code: they used an unordered data structure (set) instead of an ordered data structure (tuple):

    dict({i,j} for i,j in enumerate(lst))

It is a waste of time to slow down the dict constructor to check for something so unusual as this. Everyone will pay the cost of the checks and virtually no-one will get any benefit.

I'm closing this as "rejected", but if anyone disagrees they can reopen it.

By the way, the best way to initialise a dictionary in this situation is to avoid the unnecessary generator expression and just go straight to enumerate:

    dict(enumerate(lst))

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nosy: +steven.daprano
resolution:  -> rejected
stage:  -> resolved
status: open -> closed

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39178>
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