- bfs_edges(G, source, reverse=False, depth_limit=None, sort_neighbors=None)¶
Iterate over edges in a breadth-first-search starting at source.
- GNetworkX graph
Specify starting node for breadth-first search; this function iterates over only those edges in the component reachable from this node.
- reversebool, optional
If True traverse a directed graph in the reverse direction
- depth_limitint, optional(default=len(G))
Specify the maximum search depth
A function that takes the list of neighbors of given node as input, and returns an iterator over these neighbors but with custom ordering.
- edge: 2-tuple of nodes
Yields edges resulting from the breadth-first search.
The naming of this function is very similar to
edge_bfs(). The difference is that
edge_bfsyields edges even if they extend back to an already explored node while this generator yields the edges of the tree that results from a breadth-first-search (BFS) so no edges are reported if they extend to already explored nodes. That means
edge_bfsreports all edges while
bfs_edgesonly reports those traversed by a node-based BFS. Yet another description is that
bfs_edgesreports the edges traversed during BFS while
edge_bfsreports all edges in the order they are explored.
To get the edges in a breadth-first search:
>>> G = nx.path_graph(3) >>> list(nx.bfs_edges(G, 0)) [(0, 1), (1, 2)] >>> list(nx.bfs_edges(G, source=0, depth_limit=1)) [(0, 1)]
To get the nodes in a breadth-first search order:
>>> G = nx.path_graph(3) >>> root = 2 >>> edges = nx.bfs_edges(G, root) >>> nodes = [root] + [v for u, v in edges] >>> nodes [2, 1, 0]