On 24 January 2016 at 19:47, Albert-Jan Roskam <sjeik_ap...@hotmail.com> wrote: >> >> You appear to be confusing ordered and sorted.
> You are correct. Is there a difference in the way those terms are used > colloquially vs. in the field of Computer Science (Note: English is not my > mother tongue)? Anyway, this page seems to suggest that "Ordered" means "gets > messed up upon insertion, deletion, update: > http://stackoverflow.com/questions/1084146/what-is-the-difference-between-an-ordered-and-a-sorted-collection An ordered collection will preserve its order if not mutated. If mutated the operation will have a well defined effect on the order. For example list.append(a) adds a new element and the new element will always be at the end of the list regardless of its value. A list might be in sorted order (i.e. after you have called the .sort() method) but when you call append the new element will go at the end so that it is no longer sorted. A sorted collection has a sort key and ensures that it always has an order that corresponds to sorting by that key. So when you add a new element the container will somehow ensure that it ends up in the right position to keep the container sorted. If you use an ordered container initialised with sorted data (as you seem to be doing) then the distinction is only important if you mutate the container. Specifically in the case of an OrderedDict which you want sorted by keys the distinction is only important if you add new keys to the OrderedDict. Any new keys will be implicitly added at the end of the OrderedDict's ordering (as if you called append on a list). Removing a key with e.g. pop() is fine and changing the value associate with a key is fine: only adding new keys will break the sort order. So if you're not adding new keys to the OrderedDict as you work then there is no reason not to use it in this situation. -- Oscar _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
