On Sun, Jul 1, 2012 at 11:36 PM, Chris Smith <[email protected]> wrote: >>> Are you aware that there is now an ordered dictionary in python? It >>> was backported to 2.7.3, I believe. >> >> This looks fine, but do you some data as to the speed? [0] says that >> it keeps the items in the order in which they were inserted. That >> smells of sequential storage and thus doesn't sound terribly cool >> performance-wise, when random-access is needed. >> > > Some details at http://tinyurl.com/8y4h9ad
Awesome, thank you! This looks a lot like the implementation that has recently been discussed in this thread: a regular Python dict (i.e., hash table) accompanied by a list to know the order of the items. By the way, for versions of Python younger than 2.7, there is [0]. There is a subtle point about ordered dicts vs. dicts, however. There are algorithms which do depend on order, and those which don't. It often happens so that at implementation a dependency on the order slips by. I think this should be pointed out by the corresponding test failures. On the other hand, for algorithms which inherently need order, ordered dicts should be fine. Sergiu [0] http://pypi.python.org/pypi/ordereddict -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
