Sage Reference Manual: Graph Theory - Mirrors

Sage Reference Manual: Graph Theory, Release 6.1.1
The following syntax is supported, but note that you must use the label keyword:
sage: G = Graph()
sage: G.add_edge((1,2), label=’label’)
sage: G.edges()
[(1, 2, ’label’)]
sage: G = Graph()
sage: G.add_edge((1,2), ’label’)
sage: G.edges()
[(’label’, (1, 2), None)]
Vertex name cannot be None, so:
sage: G = Graph()
sage: G.add_edge(None, 4)
sage: G.vertices()
[0, 4]
add_edges(edges)
Add edges from an iterable container.
EXAMPLES:
sage: G = graphs.DodecahedralGraph()
sage: H = Graph()
sage: H.add_edges( G.edge_iterator() ); H
Graph on 20 vertices
sage: G = graphs.DodecahedralGraph().to_directed()
sage: H = DiGraph()
sage: H.add_edges( G.edge_iterator() ); H
Digraph on 20 vertices
add_path(vertices)
Adds a cycle to the graph with the given vertices. If the vertices are already present, only the edges are
added.
For digraphs, adds the directed path vertices[0], ..., vertices[-1].
INPUT:
•vertices - a list of indices for the vertices of the cycle to be added.
EXAMPLES:
sage: G = Graph()
sage: G.add_vertices(range(10)); G
Graph on 10 vertices
sage: show(G)
sage: G.add_path(range(20)[10:20])
sage: show(G)
sage: G.add_path(range(10))
sage: show(G)
sage: D = DiGraph()
sage: D.add_path(range(4))
sage: D.edges()
[(0, 1, None), (1, 2, None), (2, 3, None)]
add_vertex(name=None)
Creates an isolated vertex. If the vertex already exists, then nothing is done.
INPUT:
1.1. Generic graphs 7