Warning

This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.

dfs_predecessors

dfs_predecessors(G, source=None)[source]

Return dictionary of predecessors in depth-first-search from source.

Parameters:
  • G (NetworkX graph) –
  • source (node, optional) – Specify starting node for depth-first search and return edges in the component reachable from source.
Returns:

pred – A dictionary with nodes as keys and predecessor nodes as values.
Return type:

dict

Examples

>>> G = nx.Graph()
>>> G.add_path([0,1,2])
>>> print(nx.dfs_predecessors(G,0))
{1: 0, 2: 1}

Notes

Based on http://www.ics.uci.edu/~eppstein/PADS/DFS.py by D. Eppstein, July 2004.

If a source is not specified then a source is chosen arbitrarily and repeatedly until all components in the graph are searched.