Networkx graph searches: dfs_successors vs. dfs_predecessors

Question

Consider the following graph structure (borrowed from this question):

G = networkx.DiGraph()
G.add_edges_from([(\'n\', \'n1\'), (\'n\', \'n2\'), (\'n\', \'n3         


        

Answer 1

The dfs_predecessors() function only gives the immediate predecessor. So if you say this (DFS of G from node 'n' and looking back one link from 'n22')

>>> print(networkx.dfs_predecessors(G, 'n')['n221'])
n22

you get part of what you want.

To get the path in the DFS tree from n221 back to the root:

>>> T = networkx.dfs_tree(G,'n')

>>> print(networkx.shortest_path(G.reverse(),'n221','n'))
['n221', 'n22', 'n2', 'n']