networkx.algorithms.traversal.depth_first_search.dfs_predecessors¶
-
dfs_predecessors
(G, source=None, depth_limit=None)[source]¶ Returns dictionary of predecessors in depth-first-search from source.
- Parameters
G (NetworkX graph)
source (node, optional) – Specify starting node for depth-first search.
depth_limit (int, optional (default=len(G))) – Specify the maximum search depth.
- Returns
pred – A dictionary with nodes as keys and predecessor nodes as values.
- Return type
Examples
>>> G = nx.path_graph(4) >>> nx.dfs_predecessors(G, source=0) {1: 0, 2: 1, 3: 2} >>> nx.dfs_predecessors(G, source=0, depth_limit=2) {1: 0, 2: 1}
Notes
If a source is not specified then a source is chosen arbitrarily and repeatedly until all components in the graph are searched.
The implementation of this function is adapted from David Eppstein’s depth-first search function in PADS, with modifications to allow depth limits based on the Wikipedia article “Depth-limited search”.
See also
dfs_preorder_nodes()
,dfs_postorder_nodes()
,dfs_labeled_edges()
,edge_dfs()
,bfs_tree()