9.7.6.11. networkx.algorithms.shortest_paths.weighted.single_source_dijkstra_path_length¶

networkx.algorithms.shortest_paths.weighted.single_source_dijkstra_path_length(G, source, cutoff=None, weight='weight')[source]¶

Find shortest weighted path lengths in G from a source node.

Compute the shortest path length between source and all other reachable nodes for a weighted graph.

Parameters:

G : NetworkX graph source : node label Starting node for path cutoff : integer or float, optional Depth to stop the search. Only return paths with length <= cutoff. weight : string or function If this is a string, then edge weights will be accessed via the edge attribute with this key (that is, the weight of the edge joining u to v will be G.edge[u][v][weight]). If no such edge attribute exists, the weight of the edge is assumed to be one. 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.

Returns:

length : iterator (target, shortest path length) iterator

See also

single_source_dijkstra, single_source_bellman_ford_path_length

Notes

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

The weight function can be used to hide edges by returning None. So weight = lambda u, v, d: 1 if d['color']=="red" else None will find the shortest red path.

Examples

>>> G = nx.path_graph(5)
>>> length = dict(nx.single_source_dijkstra_path_length(G, 0))
>>> length[4]
4
>>> print(length)
{0: 0, 1: 1, 2: 2, 3: 3, 4: 4}