Re: [igraph] Plotting an ancestral graph

[Tamas Nepusz]

Hi Alexander,

Okay, for the record: this happens because E(g3) lists edges with the *names* 
of the endpoints, not their indices, while get.edge(g3, 2) gives you the 
*indices* of the endpoints. So, in your case, you have a graph where vertex 0 
has name "1", vertex 1 has name "2" and so on, and this is what you see in 
E(g3). V(g)$name will give you the name vector.

-- 
T.

On 2010.06.17., at 22:36, Alexander Savi wrote:

> Thank you Tamas. Strangely enough this doesn't seem to work for me, as you 
> can see below:
> 
> > E(g3)
> Edge sequence:
>           
> [0] 1 -> 2
> [1] 2 -> 1
> [2] 2 -> 5
> [3] 3 -> 4
> [4] 4 -> 3
> [5] 4 -> 5
> 
> > get.edge(g3, 2)
> [1] 1 4
> 
> If I understand you well, get.edge(g3, 2) should produce [1] 2 5. However 
> somehow it produces something else which I cannot make sense of.
> 
> Alexander
> 
> 
> 
> Alexander Savi | address@hidden | +31 (0)6 55 77 37 37
> 
> 
> On 17 June 2010 22:39, Tamas Nepusz <address@hidden> wrote:
> > Given the information below, is it possible to single out the number in 
> > front of the arrow and the number behind the arrow?
> I've found this, but I'm not sure if this is the only way or there's a better 
> way than that:
> 
> > get.edge(g3, 0)
> [1] 1 2
> > get.edge(g3, 1)
> [1] 1 4
> ...and so on. get.edge(g3, edge_index)[1] gives you the source, get.edge(g3, 
> edge_index)[2] gives you the target. Note that igraph indexes edges and 
> vertices from zero, not one; also note that this will change some time in the 
> future to become compatible with the rest of R. You can start watching this 
> bug report in Launchpad if you are interested in when it will change 
> (definitely not before igraph 0.6):
> 
> https://bugs.launchpad.net/igraph/+bug/595092
> 
> --
> Tamas
> 
> 
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