intersection_all

intersection_all(graphs)

Returns a new graph that contains only the nodes and the edges that exist in all graphs.

Parameters:

graphsiterable

Iterable of NetworkX graphs

Returns:

RA new graph with the same type as the first graph in list

Raises:

ValueError

If graphs is an empty list.

NetworkXError

In case of mixed type graphs, like MultiGraph and Graph, or directed and undirected graphs.

Notes

For operating on mixed type graphs, they should be converted to the same type.

Attributes from the graph, nodes, and edges are not copied to the new graph.

The resulting graph can be updated with attributes if desired. For example, code which adds the minimum attribute for each node across all graphs could work. >>> g = nx.Graph() >>> g.add_node(0, capacity=4) >>> g.add_node(1, capacity=3) >>> g.add_edge(0, 1)

>>> h = g.copy()
>>> h.nodes[0]["capacity"] = 2

>>> gh = nx.intersection_all([g, h])

>>> new_node_attr = {
...     n: min(*(anyG.nodes[n].get("capacity", float("inf")) for anyG in [g, h]))
...     for n in gh
... }
>>> nx.set_node_attributes(gh, new_node_attr, "new_capacity")
>>> gh.nodes(data=True)
NodeDataView({0: {'new_capacity': 2}, 1: {'new_capacity': 3}})

Examples

>>> G1 = nx.Graph([(1, 2), (2, 3)])
>>> G2 = nx.Graph([(2, 3), (3, 4)])
>>> R = nx.intersection_all([G1, G2])
>>> list(R.nodes())
[2, 3]
>>> list(R.edges())
[(2, 3)]