diff options
| -rw-r--r-- | networkx/classes/function.py | 7 | ||||
| -rw-r--r-- | networkx/classes/tests/test_function.py | 4 |
2 files changed, 10 insertions, 1 deletions
diff --git a/networkx/classes/function.py b/networkx/classes/function.py index fb24105f..a0807942 100644 --- a/networkx/classes/function.py +++ b/networkx/classes/function.py @@ -1279,7 +1279,10 @@ def number_of_selfloops(G): def is_path(G, path): - """Returns whether or not the specified path exists + """Returns whether or not the specified path exists. + + For it to return True, every node on the path must exist and + each consecutive pair must be connected via one or more edges. Parameters ---------- @@ -1296,6 +1299,8 @@ def is_path(G, path): """ for node, nbr in nx.utils.pairwise(path): + if node not in G: + return False if nbr not in G[node]: return False return True diff --git a/networkx/classes/tests/test_function.py b/networkx/classes/tests/test_function.py index 051d655c..df17f200 100644 --- a/networkx/classes/tests/test_function.py +++ b/networkx/classes/tests/test_function.py @@ -771,12 +771,16 @@ def test_pathweight(): def test_ispath(): valid_path = [1, 2, 3, 4] invalid_path = [1, 2, 4, 3] + another_invalid_path = [1, 2, 3, 4, 5] + yet_another_invalid_path = [1, 2, 5, 3, 4] graphs = [nx.Graph(), nx.DiGraph(), nx.MultiGraph(), nx.MultiDiGraph()] edges = [(1, 2), (2, 3), (1, 2), (3, 4)] for graph in graphs: graph.add_edges_from(edges) assert nx.is_path(graph, valid_path) assert not nx.is_path(graph, invalid_path) + assert not nx.is_path(graph, another_invalid_path) + assert not nx.is_path(graph, yet_another_invalid_path) @pytest.mark.parametrize("G", (nx.Graph(), nx.DiGraph())) |