[Python-Dev] LinkedHashSet/LinkedHashMap equivalents (original) (raw)

Nick Coghlan ncoghlan at iinet.net.au
Thu Mar 10 12:49:34 CET 2005

Delaney, Timothy C (Timothy) wrote:

OTOH, "ordered set" and "ordered dict" implies different things to different people - usually "sorted" rather than "the order things were put in". Perhaps "temporally-ordered" ;)

OTGH*, I would expect an OrderedDict / OrderedSet to have 'add to the end' semantics, but also provide a 'sort()' method so that the ordering could be changed at a later date.

IOW, by default the ordering is temporal. Sorting the ordered dict/set changes the iteration order for the current contents. Further additions are still added in temporal order until such time as the dict/set is sorted again.

The parallels are to using list.append() to build a list, and list.sort() to order the current contents (in fact, a simplistic approach could use that exact technique to remember the order of keys, at the cost of doubling key storage requirements).

Cheers, Nick.

*OTGH: On the gripping hand :)

-- Nick Coghlan | ncoghlan at email.com | Brisbane, Australia

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