# union_all#

union_all(graphs, rename=())[source]#

Returns the union of all graphs.

The graphs must be disjoint, otherwise an exception is raised.

Parameters:
graphsiterable

Iterable of NetworkX graphs

renameiterable , optional

Node names of graphs can be changed by specifying the tuple rename=(‘G-‘,’H-’) (for example). Node “u” in G is then renamed “G-u” and “v” in H is renamed “H-v”. Infinite generators (like itertools.count) are also supported.

Returns:
Ua 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.

`union`
`disjoint_union_all`

Notes

For operating on mixed type graphs, they should be converted to the same type. >>> G = nx.Graph() >>> H = nx.DiGraph() >>> GH = union_all([nx.DiGraph(G), H])

To force a disjoint union with node relabeling, use disjoint_union_all(G,H) or convert_node_labels_to integers().

Graph, edge, and node attributes are propagated to the union graph. If a graph attribute is present in multiple graphs, then the value from the last graph in the list with that attribute is used.

Examples

```>>> G1 = nx.Graph([(1, 2), (2, 3)])
>>> G2 = nx.Graph([(4, 5), (5, 6)])
>>> result_graph = nx.union_all([G1, G2])
>>> result_graph.nodes()
NodeView((1, 2, 3, 4, 5, 6))
>>> result_graph.edges()
EdgeView([(1, 2), (2, 3), (4, 5), (5, 6)])
```