# Convert Sage's Graph to NetworkX graph

I want to use a function of networkx. More specifically I want to use the function

double_edge_swap()


provided in the networkx package included in Sage. For more information see here.

But, I have a Sage graph constructed with:

Graph()


So I want to convert the Sage's Graph() object to a networkx object. How I do that?

Best regards.

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You can simply call the method .networkx_graph():

sage: import networkx as nx
sage: G = graphs.PetersenGraph()
sage: ng = G.networkx_graph()
sage: ng
<networkx.classes.graph.Graph object at 0xd3c2f8c>
sage: nx.double_edge_swap(ng)
1


Incidentally, I didn't know this five minutes ago, so I should tell you how I found out. Lots of functionality for Sage objects lives inside them, in methods. Typically conversion functions are either called ".targettype" or "._targettype_", so I tried

sage: G.netw[HERE I HIT TAB]
G.networkx_graph


which looked promising. And then typing

sage: G.networkx_graph?


gives the documentation:

       Creates a new NetworkX graph from the Sage graph.

INPUT:

* "copy" - if False, and the underlying implementation is a
NetworkX graph, then the actual object itself is returned.

EXAMPLES:

sage: G = graphs.TetrahedralGraph()
sage: N = G.networkx_graph()
sage: type(N)
<class 'networkx.classes.graph.Graph'>

sage: G = graphs.TetrahedralGraph()
sage: G = Graph(G, implementation='networkx')
sage: N = G.networkx_graph()
sage: G._backend._nxg is N
False

sage: G = Graph(graphs.TetrahedralGraph(), implementation='networkx')
sage: N = G.networkx_graph(copy=False)
sage: G._backend._nxg is N
True


PS: Okay, to be perfectly honest, I tried it first and only looked at the documentation when I came to write this. But I would've looked at the documentation if it hadn't worked, I promise! :^)

more

Thanks very much DSM. That solves my problem. Fool of me. I tried using TAB in sage's notebook, and googled a lot. But I couldn't find it.

( 2012-02-13 05:31:33 -0500 )edit
1

To get this, you need to do G.[tab], not G[tab]. In case that's where the confusion came in.

( 2012-02-13 06:50:18 -0500 )edit