orderedset 2.0

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 2.6 through 3.4.;
• Supports the full set interface;
• Supports some list methods, like \(index\) and \(__getitem__\).
• Supports set methods against iterables.

Changelog

2.0 - 2016-02-02

• breaking change: All comparisons, other than \(eq\), against other ordered sets are now performed unordered; i.e., they are treated as regular sets.
• \(isorderedsubset\) and \(isorderedsuperset\) have been added to perform ordered comparisons against other sequences. Using these methods with unordered collections wield yield arbitrary (and depending on Python implementation, unstable) results.

1.2 - 2015-09-29

• bugfix: Set operations only worked with iterables if the OrderedSet was on the left-hand side. They now work both ways.
• bugfix: The order of an intersection was the right-hand side’s order. It is now fixed to be the left-hand side’s order.

1.1.2 - 2014-10-02

• Make comparisons work with sets and lists, and not crash when compared with None.

1.1.1 - 2014-08-24

• Add pickle/copy support to OrderedSet

1.1 - 2014-06-04

• Make OrderedSets handle slicing in __getitem__().

1.0.2 - 2014-05-14

• Add proper attribution and licenses.

1.0.1 - 2014-05-13

• Don’t require Cython to build an sdist.

1.0 - 2014-05-11

• First implementation.