On Sun, 15 Jun 2008 05:12:38 pm Raymond Hettinger wrote:
With an odict that preserves insertion order, you're talking about *deleting* the old entry and *appending* the new one, complete with both the new key and new value.
I certainly don't consider updating an ordered dictionary entry as a deletion followed by an append. In fact, I'd be very surprised, and dismayed, if that was the default behaviour.
Conceptually, I would expect the following behaviour:
od = odict() od = 'spam' # insert a new key od = 'parrot' # insert a new key od = 'ham' # modify existing key od.items()
[(1, 'ham'), (2, 'parrot')]
If I wanted the alternative behaviour, I could easily get it:
od = odict() od = 'spam' # insert a new key od = 'parrot' # insert a new key od.pop(1, None); od = 'ham' # remove and re-insert a key od.items()
[(2, 'parrot'), (1, 'ham')]
Earlier, Raymond also asked what to do about keys with equal but not identical keys. Since I consider setting the value to be an update rather than a deletion plus re-insertion, then the behaviour is obvious.
od = odict([(1, 'norwegian blue'), (2, 'parrot')]) od[1.0] = 'norwegian red' od.items()
[(1, 'norwegian red'), (2, 'parrot')]
This is close to the behaviour of regular dicts, and to do differently would be very surprising to me. Again, anyone who wants the alternative behaviour can get it easily, with a pop and a set.
+1 for an ordered dictionary.
As for a sorted dictionary, I don't care much, so +0. You can always sort the keys when you need them.