shortest_path_length(G, source=None, target=None, weight=None, method='dijkstra')
The length of the path is always 1 less than the number of nodes involved in the path since the length measures the number of edges followed.
For digraphs this returns the shortest directed path length. To find path lengths in the reverse direction use G.reverse(copy=False) first to flip the edge orientation.
Starting node for path. If not specified, compute shortest path lengths using all nodes as source nodes.
Ending node for path. If not specified, compute shortest path lengths using all nodes as target nodes.
If None, every edge has weight/distance/cost 1. If a string, use this edge attribute as the edge weight. Any edge attribute not present defaults to 1. If this is a function, the weight of an edge is the value returned by the function. The function must accept exactly three positional arguments: the two endpoints of an edge and the dictionary of edge attributes for that edge. The function must return a number.
The algorithm to use to compute the path length. Supported options: 'dijkstra', 'bellman-ford'. Other inputs produce a ValueError. If :None:None:`weight` is None, unweighted graph methods are used, and this suggestion is ignored.
If :None:None:`source` is not in G.
If no path exists between source and target.
If :None:None:`method` is not among the supported options.
If the source and target are both specified, return the length of the shortest path from the source to the target.
If only the source is specified, return a dict keyed by target to the shortest path length from the source to that target.
If only the target is specified, return a dict keyed by source to the shortest path length from that source to the target.
If neither the source nor target are specified, return an iterator over (source, dictionary) where dictionary is keyed by target to shortest path length from source to that target.
Compute shortest path lengths in the graph.
>>> G = nx.path_graph(5)
... nx.shortest_path_length(G, source=0, target=4) 4
>>> p = nx.shortest_path_length(G, source=0) # target not specified
... p[4] 4
>>> p = nx.shortest_path_length(G, target=4) # source not specified
... p[0] 4
>>> p = dict(nx.shortest_path_length(G)) # source,target not specifiedSee :
... p[0][4] 4
The following pages refer to to this document either explicitly or contain code examples using this.
networkx.algorithms.simple_paths._bidirectional_dijkstra
networkx.algorithms.shortest_paths.unweighted.single_target_shortest_path_length
networkx.algorithms.shortest_paths.unweighted.single_source_shortest_path_length
networkx.algorithms.shortest_paths.weighted.bidirectional_dijkstra
networkx.algorithms.flow.networksimplex.network_simplex
networkx.algorithms.shortest_paths.generic.shortest_path_length
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