bfs_tree#

bfs_tree(G, source, reverse=False, depth_limit=None, sort_neighbors=None)[source]#

Returns an oriented tree constructed from of a breadth-first-search starting at source.

Parameters:

GNetworkX graph
sourcenode: Specify starting node for breadth-first search
reversebool, optional: If True traverse a directed graph in the reverse direction
depth_limitint, optional(default=len(G)): Specify the maximum search depth
sort_neighborsfunction (default=None): A function that takes an iterator over nodes as the input, and returns an iterable of the same nodes with a custom ordering. For example, sorted will sort the nodes in increasing order.

Returns:

T: NetworkX DiGraph: An oriented tree

See also

dfs_tree
bfs_edges
edge_bfs

Notes

Based on http://www.ics.uci.edu/~eppstein/PADS/BFS.py by D. Eppstein, July 2004. The modifications to allow depth limits based on the Wikipedia article “Depth-limited-search”.

Examples

>>> G = nx.path_graph(3)
>>> list(nx.bfs_tree(G, 1).edges())
[(1, 0), (1, 2)]
>>> H = nx.Graph()
>>> nx.add_path(H, [0, 1, 2, 3, 4, 5, 6])
>>> nx.add_path(H, [2, 7, 8, 9, 10])
>>> sorted(list(nx.bfs_tree(H, source=3, depth_limit=3).edges()))
[(1, 0), (2, 1), (2, 7), (3, 2), (3, 4), (4, 5), (5, 6), (7, 8)]

Additional backends implement this function

cugraphGPU-accelerated backend.: sort_neighbors parameter is not yet supported.