Ordered Set

An Ordered Set implementation in Cython. Based on Raymond Hettinger's OrderedSet recipe.

Example:

>>> from orderedset import OrderedSet
>>> oset = OrderedSet([1, 2, 3])
>>> oset
OrderedSet([1, 2, 3])
>>> oset | [5, 4, 3, 2, 1]
OrderedSet([1, 2, 3, 5, 4])

• Free software: BSD license
• Documentation: http://orderedset.rtfd.org.

Features

• Works like a regular set, but remembers insertion order;
• Is approximately 5 times faster than the pure Python implementation overall (and 5 times slower than set);
• Compatible with Python 2.7 through 3.8;
• Supports the full set interface;
• Supports some list methods, like index and __getitem__.
• Supports set methods against iterables.