On Thu, Jul 9, 2020 at 9:16 PM Steven D'Aprano <steve@pearwood.info> wrote:
Unless I have missed any others, we've only seen three use-cases:
(a) The original post wanted a full sequence API for dictionaries, with the ability to insert keys at a specific index, not just get the N-th key. Not going to happen.
(b) You've suggested "get any item", but that's probably better written as `next(mydict.items)`.
(c) And `random.choice(mydict.items())` which seems to be lacking any *concrete* use-case -- under what circumstances would we want this and care about it's performance *enough* to add this to builtin dict views?
Getting a random element from a dict (not an arbitrary one but a random one) definitely does have a use-case. I've wanted it at times. Usually if I'm doing this in Python, I just pay the price and build the list, but as proof that it's a logical and useful operation, here's Pike's general random function: http://pike.lysator.liu.se/generated/manual/modref/ex/predef_3A_3A/random.ht... If given a number, it picks a random number. If given an array, it picks a random element. And if given a mapping (dictionary), it returns (key,value), without first converting to a flat list. I don't think the use-case is strong enough, since there are many possible variants you might want (imagine using collections.Counter to define a weighted average - it'd be handy to say "pick a random element, treating this as a bag/multiset"), so it's best to just custom write it when you need it. But if it's needed, it would want to be on the dictionary itself, not on the views, IMO. ChrisA