Python script to find unconnected regions

unconnected-regions.py

#!/usr/bin/env python

import networkx
import glob
import os.path

def get_subgraphs(regionset_path):
    graph = networkx.Graph()
    graph.add_nodes_from(get_nodes(regionset_path))
    add_node_edges(graph)

    return networkx.connected_component_subgraphs(graph)

def add_node_edges(graph):
    offsets = (-1, 1)
    nodes = graph.nodes()
    for node in nodes:
        for offset in offsets:
            graph.add_edges_from((node,offset_node) for offset_node in \
                [(node[0] + offset, node[1]), (node[0], node[1] + offset), (node[0] + offset, node[1] + offset)] \
                if offset_node in nodes)
    return graph

def get_nodes(regionset_path):
    return [(int(p[1]), int(p[2])) \
        for p in (f.split('.') \
            for f in glob.glob(os.path.join(regionset_path, 'r.*.*.mca')))]

if __name__ == '__main__':
    import sys

    subgraphs = sorted(get_subgraphs(sys.argv[1]))
    print 'Total regions: %d' % sum(len(g) for g in subgraphs)
    print 'Found %d discrete sections' % len(subgraphs)
    print '-> %s' % ', '.join(str(len(sg)) for sg in subgraphs)