An interval set (provided as the ProcSet class) is a memory-efficient representation of closed-interval sets. A ProcSet is an hybrid between a set and a list of indexes. More precisely, a ProcSet object is an ordered collection of unique non-negative int. It supports most of set operations: notably membership testing, mathematical operations such as intersection, union, and (symmetric) difference; with the additional ability to access its elements by position.

This is the Python 3 package.