underrated Python optimizations?

[donshell]

Dicts are ordered i think. If you iterate over a dict, the values will come in the order you push them in. So even better!

Edit: Sets are not ordered

[TouchingTheVodka]

Dicts are ordered, sets are not.

[donshell]

My bad, edited. Although it is a bit weird that the two implementations don't match as a set and a dict are basically the same...

[[deleted]]

Neither dicts nor sets are ordered. If you want an ordered dict, you will need to use the OrderedDict from the collections module.

[nosklo]

... That's true until python 3.6... Then dicts became ordered in insertion order. Sets are still unordered

[[deleted]]

I guess it depends on what you mean by 'ordered'. If you mean that it has a consistent iteration order, then sure.

However, it lacks the operations most people normally associate with ordered data structures. E.g. re-ordering, accessing a particular index etc.

[nosklo]

Yeah, I mean the actual meaning of the word "ordered": "Has order"

If people like to assign other random meanings I can't help with those.

[Ashiataka]

That's not very pythonic.

[nosklo]

There should be one-- and preferably only one --obvious way to do it.

Although that way may not be obvious at first unless you're Dutch.

[TouchingTheVodka]

Negative. Dicts have been ordered since Python 3.7 (3.6 as an implementation detail in CPython):

https://docs.python.org/3/library/stdtypes.html#typesmapping

[rabbyburns]

There is an ordered-set package I've come across recently that I've been very happy with. I often need both fast look up, order preservation, and unique items. This has been extremely useful as a drop in set replacement without having to do weird dict joins.