On Fri, 28 Apr 2006 14:27:00 -0700, nikie wrote: > Steven Bethard wrote: > >> >>> L = ['C', 'A', 'D', 'B'] >> >>> positions = dict((item, i) for i, item in enumerate(L))
Do you need the generator expression here? dict(enumerate(L)) should be equivalent, no? > Isn't this bound to be less efficient? I mean, inserting the items into > a dict is probably O(n log n), which is definitely worse than O(n) for > searching the list twice. And, of course, it would yield different > results if 'A' or 'D' are in the list more than once. Although presumably the dict method might be quicker if you were comparing the positions a large number of times. Incidentally, does python have a built-in to do a binary search on a sorted list? Obviously it's not too tricky to write one, but it would be nice if there was one implemented in C. -- http://mail.python.org/mailman/listinfo/python-list
