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networkx.algorithms.traversal.breadth_first_search.bfs_predecessors

bfs_predecessors(G, source)[source]

Returns an iterator of predecessors in breadth-first-search from source.

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

pred – (node, predecessors) iterator where predecessors is the list of predecessors of the node.
Return type:

iterator

Examples

>>> G = nx.path_graph(3)
>>> print(dict(nx.bfs_predecessors(G, 0)))
{1: 0, 2: 1}
>>> H = nx.Graph()
>>> H.add_edges_from([(0, 1), (0, 2), (1, 3), (1, 4), (2, 5), (2, 6)])
>>> dict(nx.bfs_predecessors(H, 0))
{1: 0, 2: 0, 3: 1, 4: 1, 5: 2, 6: 2}

Notes

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