networkx.algorithms.shortest_paths.weighted.dijkstra_path_length¶
-
dijkstra_path_length
(G, source, target, weight='weight')[source]¶ Returns the shortest weighted path length in G from source to target.
Uses Dijkstra’s Method to compute the shortest weighted path length between two nodes in a graph.
- Parameters
G (NetworkX graph)
source (node label) – starting node for path
target (node label) – ending node for path
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
tov
will beG.edges[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 – Shortest path length.
- Return type
number
- Raises
NodeNotFound – If
source
is not inG
.NetworkXNoPath – If no path exists between source and target.
Examples
>>> G = nx.path_graph(5) >>> print(nx.dijkstra_path_length(G, 0, 4)) 4
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.The function
single_source_dijkstra()
computes both path and length-of-path if you need both, use that.