predecessor#
- predecessor(G, source, target=None, cutoff=None, return_seen=None)[source]#
Returns dict of predecessors for the path from source to all nodes in G.
- Parameters:
- GNetworkX graph
- sourcenode label
Starting node for path
- targetnode label, optional
Ending node for path. If provided only predecessors between source and target are returned
- cutoffinteger, optional
Depth to stop the search. Only paths of length <= cutoff are returned.
- return_seenbool, optional (default=None)
Whether to return a dictionary, keyed by node, of the level (number of hops) to reach the node (as seen during breadth-first-search).
- Returns:
- preddictionary
Dictionary, keyed by node, of predecessors in the shortest path.
- (pred, seen): tuple of dictionaries
If
return_seen
argument is set toTrue
, then a tuple of dictionaries is returned. The first element is the dictionary, keyed by node, of predecessors in the shortest path. The second element is the dictionary, keyed by node, of the level (number of hops) to reach the node (as seen during breadth-first-search).
Examples
>>> G = nx.path_graph(4) >>> list(G) [0, 1, 2, 3] >>> nx.predecessor(G, 0) {0: [], 1: [0], 2: [1], 3: [2]} >>> nx.predecessor(G, 0, return_seen=True) ({0: [], 1: [0], 2: [1], 3: [2]}, {0: 0, 1: 1, 2: 2, 3: 3})