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| -rw-r--r-- | networkx/classes/function.py | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/networkx/classes/function.py b/networkx/classes/function.py index 7707ec4c..fb24105f 100644 --- a/networkx/classes/function.py +++ b/networkx/classes/function.py @@ -786,6 +786,11 @@ def set_edge_attributes(G, values, name=None): >>> G[1][2]["attr2"] 3 + The attributes of one Graph can be used to set those of another. + + >>> H = nx.path_graph(3) + >>> nx.set_edge_attributes(H, G.edges) + Note that if the dict contains edges that are not in `G`, they are silently ignored:: @@ -794,6 +799,29 @@ def set_edge_attributes(G, values, name=None): >>> (1, 2) in G.edges() False + For multigraphs, the `values` dict is expected to be keyed by 3-tuples + including the edge key:: + + >>> MG = nx.MultiGraph() + >>> edges = [(0, 1), (0, 1)] + >>> MG.add_edges_from(edges) # Returns list of edge keys + [0, 1] + >>> attributes = {(0, 1, 0): {"cost": 21}, (0, 1, 1): {"cost": 7}} + >>> nx.set_edge_attributes(MG, attributes) + >>> MG[0][1][0]["cost"] + 21 + >>> MG[0][1][1]["cost"] + 7 + + If MultiGraph attributes are desired for a Graph, you must convert the 3-tuple + multiedge to a 2-tuple edge and the last multiedge's attribute value will + overwrite the previous values. Continuing from the previous case we get:: + + >>> H = nx.path_graph([0, 1, 2]) + >>> nx.set_edge_attributes(H, {(u, v): ed for u, v, ed in MG.edges.data()}) + >>> nx.get_edge_attributes(H, "cost") + {(0, 1): 7} + """ if name is not None: # `values` does not contain attribute names |