# networkx.algorithms.shortest_paths.weighted.bellman_ford_path_length¶

bellman_ford_path_length(G, source, target, weight='weight')[source]

Returns the shortest path length from source to target in a weighted graph.

Parameters
• G (NetworkX graph)

• source (node label) – starting node for path

• target (node label) – ending node for path

• weight (string, optional (default=’weight’)) – Edge data key corresponding to the edge weight

Returns

length – Shortest path length.

Return type

number

Raises
• NodeNotFound – If source is not in G.

• NetworkXNoPath – If no path exists between source and target.

Examples

>>> G=nx.path_graph(5)
>>> print(nx.bellman_ford_path_length(G,0,4))
4


Notes

Edge weight attributes must be numerical. Distances are calculated as sums of weighted edges traversed.