On 15 December 2017 at 05:28, Raymond Hettinger <raymond.hettin...@gmail.com> wrote: > In contrast, I gave collections.OrderedDict a different design (later coded > in C by Eric Snow). The primary goal was to have efficient maintenance of > order even for severe workloads such at that imposed by the lru_cache which > frequently alters order without touching the underlying dict. > Intentionally, the OrderedDict has a design that prioritizes ordering > capabilities at the expense of additional memory overhead and a constant > factor worse insertion time.
That's interesting information - I wasn't aware of the different performance goals. I'd suggest adding a discussion of these goals to the OrderedDict documentation. Now that dictionaries preserve order (whether or not we make that language guaranteed or an implementation detail) having clear information on the intended performance trade-offs of an OrderedDict would help people understand why they might choose one over the other. Paul _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
