Mark Summerfield wrote:
> - If an item is inserted it is put in the right place (because the
> underlying data structure, b*tree, skiplist or whatever is
> intrinsically ordered by < on the key)
+1 for all your suggestions below, but -1 for the above. You suggest that
myOrderedDict['key'] = value
would place it in the dictionary in sorted order depending on 'key'.
More natural to some of us (or maybe its just me) would be to append the
key/value pair to the end of items.
My Argument: The problem with inserting at sorted position is the
assumption that the dict is already sorted, but maybe I want the key
ordering to reflect something arbitrary, like a database, etc (e.g.
'Last', 'First', 'MI'). So now I assign to an OrderedDict that already
has these latter 3 keys:
myOrderedDict['Favorite Color'] = 'chartruse'
Where does it go? Answer: it probably depends on how the underlying
sorter works and (even worse) the internal state of the sorter's data
structure. So, my intuition is that SortedDict behavior should be kept
distinct from OrderedDict behavior.
> - Extra methods
> key_at(index : int) -> key
> item_at(index : int) -> (key, value)
> value_at(index : int) -> value
> set_value_at(index : int, value) # no return value necessary but
> maybe key if convenient
> od[x:y:z] -> list of values ordered by key # can read a slice but
> not assign a slice
I do not see why assigning a slice is a bad idea here. The behavior
could be such:
od = OrderedDict((('Last':'Smith'), ('First':'John'), ('MI':'J'))
od[:1] = ['Brown']
od[:2] = ['Glotz', 'Joe']
od[:2] = ['Williams', 'Mary', 'Francis'] # <== ValueError
The latter would be a phenomenon similar to unpacking a tuple of the
wrong length.
> and maybe
> keys_for(fromindex : int, uptobutexcludingindex : int) -> ordered
> list of keys
Of course the naming is redundant for these in my opinion. E.g.:
key_at -> key
item_at -> item
value_at -> value
set_value_at -> set_value (not simply set)
keys_for -> keys (takes optional argument(s))
James
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