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


predecessor(G, source, target=None, cutoff=None, return_seen=None)[source]

Returns dictionary of predecessors for the path from source to all nodes in G.

Parameters :

G : NetworkX graph

source : node label

Starting node for path

target : node label, optional

Ending node for path. If provided only predecessors between source and target are returned

cutoff : integer, optional

Depth to stop the search. Only paths of length <= cutoff are returned.

Returns :

pred : dictionary

Dictionary, keyed by node, of predecessors in the shortest path.


>>> G=nx.path_graph(4)
>>> print(G.nodes())
[0, 1, 2, 3]
>>> nx.predecessor(G,0)
{0: [], 1: [0], 2: [1], 3: [2]}