Cluster node names being typically indexed, common node sets rely heavily on numerical range sets. The :mod:`.RangeSet` module provides two public classes to deal directly with such range sets, :class:`.RangeSet` and :class:`.RangeSetND`, presented in the following sections.
The :class:`.RangeSet` class implements a mutable, ordered set of cluster node indexes (one dimension) featuring a fast range-based API. This class is used by the :class:`.NodeSet` class (see :ref:`class-NodeSet`). Since version 1.6, :class:`.RangeSet` really derives from standard Python set class (Python sets), and thus provides methods like :meth:`.RangeSet.union`, :meth:`.RangeSet.intersection`, :meth:`.RangeSet.difference`, :meth:`.RangeSet.symmetric_difference` and their in-place versions :meth:`.RangeSet.update`, :meth:`.RangeSet.intersection_update`, :meth:`.RangeSet.difference_update()` and :meth:`.RangeSet.symmetric_difference_update`.
Since v1.6, padding of ranges (eg. 003-009) can be managed through a public :class:`.RangeSet` instance variable named padding. It may be changed at any time. Padding is a simple display feature per RangeSet object, thus current padding value is not taken into account when computing set operations. Also since v1.6, :class:`.RangeSet` is itself an iterator over its items as integers (instead of strings). To iterate over string items as before (with optional padding), you can now use the :meth:`.RangeSet.striter()` method.
The :class:`.RangeSetND` class builds a N-dimensional RangeSet mutable object and provides the common set methods. This class is public and may be used directly, however we think it is less convenient to manipulate that :class:`.NodeSet` and does not necessarily provide the same one-dimension optimization (see :ref:`class-NodeSet-nD`). Several constructors are available, using RangeSet objects, strings or individual multidimensional tuples, for instance:
>>> from ClusterShell.RangeSet import RangeSet, RangeSetND
>>> r1 = RangeSet("1-5/2")
>>> r2 = RangeSet("10-12")
>>> r3 = RangeSet("0-4/2")
>>> r4 = RangeSet("10-12")
>>> print r1, r2, r3, r4
1,3,5 10-12 0,2,4 10-12
>>> rnd = RangeSetND([[r1, r2], [r3, r4]])
>>> print rnd
0-5; 10-12
>>> print list(rnd)
[(0, 10), (0, 11), (0, 12), (1, 10), (1, 11), (1, 12), (2, 10), (2, 11), (2, 12), (3, 10), (3, 11), (3, 12), (4, 10), (4, 11), (4, 12), (5, 10), (5, 11), (5, 12)]
>>> r1 = RangeSetND([(0, 4), (0, 5), (1, 4), (1, 5)])
>>> len(r1)
4
>>> str(r1)
'0-1; 4-5\n'
>>> r2 = RangeSetND([(1, 4), (1, 5), (1, 6), (2, 5)])
>>> str(r2)
'1; 4-6\n2; 5\n'
>>> r = r1 & r2
>>> str(r)
'1; 4-5\n'
>>> list(r)
[(1, 4), (1, 5)]