Question

python networkx模块里面计算最短路径时，如何处理等价路径？我怎么测试只能显示1条路径，请大神赐教。

import networkx as nx
G = nx.MultiDiGraph()
G.add_nodes_from (['北京','上海''广东''辽宁'])
G.add_weighted_edges_from ([('北京','上海',2000) ,('北京','辽宁',2000) ,('上海','广东',2000),('辽宁','广东',2000)] )
pos = nx.spring_layout(G)
path = nx.dijkstra_path(G,source="北京",target= "广东")
length = nx.dijkstra_path_length(G,source="北京",target= "广东")
print (path)
print (length)
程序运行的结果如下，按理来说，北京-上海-广东、北京-辽宁-广东这2条路径是等价的。
['北京', '上海', '广东']
4000

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Answer 1

if source is None: if target is None: ## Find paths between all pairs. if weight is None: paths=nx.all_pairs_shortest_path(G) else: paths=nx.all_pairs_dijkstra_path(G,weight=weight) else: ## Find paths from all nodes co-accessible to the target. directed = G.is_directed() if directed: G.reverse(copy=False) if weight is None: paths=nx.single_source_shortest_path(G,target) else: paths=nx.single_source_dijkstra_path(G,target,weight=weight) # Now flip the paths so they go from a source to the target. for target in paths: paths[target] = list(reversed(paths[target])) if directed: G.reverse(copy=False) else: if target is None: ## Find paths to all nodes accessible from the source. if weight is None: paths=nx.single_source_shortest_path(G,source) else: paths=nx.single_source_dijkstra_path(G,source,weight=weight) else: ## Find shortest source-target path. if weight is None: paths=nx.bidirectional_shortest_path(G,source,target) else: paths=nx.dijkstra_path(G,source,target,weight)