dijkstra_path(G, source, target, weight='weight')¶
Returns the shortest weighted path from source to target in G.
Uses Dijkstra’s Method to compute the shortest weighted path between two nodes in a graph.
G (NetworkX graph)
source (node) – Starting node
target (node) – Ending node
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
G.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.
path – List of nodes in a shortest path.
- Return type
>>> G = nx.path_graph(5) >>> print(nx.dijkstra_path(G, 0, 4)) [0, 1, 2, 3, 4]
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 Nonewill find the shortest red path.
The weight function can be used to include node weights.
>>> def func(u, v, d): ... node_u_wt = G.nodes[u].get("node_weight", 1) ... node_v_wt = G.nodes[v].get("node_weight", 1) ... edge_wt = d.get("weight", 1) ... return node_u_wt / 2 + node_v_wt / 2 + edge_wt
In this example we take the average of start and end node weights of an edge and add it to the weight of the edge.
single_source_dijkstra()computes both path and length-of-path if you need both, use that.