Hello,
Let me consider a graph that I often need to use: the graph with one vertex and three loops.
sage: G = DiGraph([(0,0,'a'), (0,0,'b'), (0,0,'c')])
Is there a way to change the labels after the creation? Because
sage: G.set_edge_label(0,0,'d')
Traceback (most recent call last):
...
RuntimeError: Cannot set edge label, since there are multiple edges from 0 to 0.
Vincent
Of course you would have to specify which label will be replaced by 'd'. I did not found such a method in Sage (and unfortunately the .set_edge_label() method does not offer the possibility to specify which edge you would like to relabel), but you can always fallback to:
sage: G.edges()
[(0, 0, 'a'), (0, 0, 'b'), (0, 0, 'c')]
sage: G.delete_edge((0,0,'b'))
sage: G.add_edge((0,0,'d'))
sage: G.edges()
[(0, 0, 'a'), (0, 0, 'c'), (0, 0, 'd')]
Asked: 2015-01-31 21:01:13 +0100
Seen: 1,388 times
Last updated: Jan 31 '15
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