INADA Naoki added the comment: I think typical usage is: get, set (incl, creating), and iterate.
* get: there is no difference * set: inserting new key is little faster since no updating linked list * iterate: in typical case, new odict is faster because current odict iterator do lookup for each key. $ ./py-patched -m perf timeit --compare-to `pwd`/py-default \ -s 'from collections import OrderedDict as odict; od = odict.fromkeys(range(10000))' -- 'list(od)' py-default: ..................... 223 us +- 10 us py-patched: ..................... 93.7 us +- 3.3 us Mean +- std dev: [py-default] 223 us +- 10 us -> [py-patched] 93.7 us +- 3.3 us: 2.38x faster (-58%) On the other hand, there are some cases new odict is slower: * iterating sparse dict. (but same speed as normal dict) * comparing two odict, because new odict do `list(od1) == list(od2)` to compare keys. For now, new odict uses dict's iterator (with adding `reversed` order support) and it's weak against modify while iterating. That's why I used temporal list while comparing. And there is one failing test for modify-while-iterate case. So I'm thinking about implementing robust odict iterator which detect modify for now. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue31265> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
