在有向图中查找任何给定两个节点之间的所有可能最短路径时如何处理错误

Question

I have a directed graph including string nodes and I need to find all shortest paths between any two given nodes of it. As between some of the nodes there is no path, nx.shortest_path() gives error. I tried the code below to do handle the error and force the program to continue after facing an error:

import networkx as nx


G2 = nx.DiGraph()

G2.add_edges_from([('A','B'),('A','C'),('A','D'),('A','F'),('F','G'),('F','H'),('H','I'),('A','I')])

N = list(G2.nodes)

nx.draw(G2, with_labels=1)

try :
    for i in range(len(G2.nodes)) :
        for j in range(len(G2.nodes)) :
         print(nx.shortest_path(G2,N[i],N[j]))
         print(i,j)
except Exception :
    pass

the problem is that the program stops when it comes to i=0, j=2. Is anything wrong with the code causing this?

Answer 1

Looks to me like you just want nx.all_pairs_shortest_path(G) . Be careful if you need to consider weights or if it matters when there are ties for shortest path in the graph.

In case that doesn't exactly fit your needs I'd also encourage you to look at the reference documentation for all shortest path algorithms especially at any function that starts with all_pairs_ ...