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Hello all,

First, thank you Moses for your advice. I have been trying in R statnet to
mimic  what you did in python. I am running into problem however, and hope
someone can help.

From what I can tell, the ego networks generated with ego.extract() is not
stored as a separate matrix, but appears to be an object that is still
associated with my original network. I want to convert it to a unique
matrix so that I can remove the focal node and merge it with other ego
networks as Moses described.

Her is an example to illustrate what I mean.

The following code:

ego224 = ego.extract(mx, ego=224, neighborhood = "combined")
ego224net = as.matrix(ego224)

gives me this:

> ego224net
      [,1]
   AA Integer,7396

Does anyone know how I can convert the ego network generated by
ego.network() to a format that I can then delete nodes from and merge with
other networks?

Again, *my overall goa*l is to create an "ego" network from two focal
nodes, to exclude those nodes in the "two-ego" network, and then calculate
density, centerlization, and other measures on the "two-ego" network. So if
you know another way to do this, feel free to tell me I am on the wrong
path and set me straight.

More details of my ultimate goal:

Would anyone know how to extract an ego-neighborhood for two nodes in the
SNA R package?

I know that ego.extract will allow me to extract ego neighborhoods for
specific nodes, but I want to extract the combined neighborhood for two
nodes (that is all nodes connected to nodes 3 or 4, for example).

I then need to calculate size, density, and centralization on each
extracted ego neighborhood. For these measures,  I need to exclude the
focal nodes. Can I exclude the focal nodes from the resulting ego network
when using ego.extract?



On Sat, Feb 22, 2014 at 3:59 AM, Moses Boudourides <
[log in to unmask]> wrote:

> Jesse, I'm afraid I don't know how to do this in the SNA R package
> (since I'm not using R that often) but I can show you how it is done
> using Python's NetworkX - I guess you just need to apply similar
> functions in SNA:
>
> First, how to extract the 2--ego network:
>
> >>> G = nx.barabasi_albert_graph(20,3)
> >>> G.nodes()
> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
> >>> G.edges()
> [(0, 3), (0, 4), (0, 5), (0, 6), (0, 8), (0, 12), (1, 11), (1, 9), (1,
> 3), (1, 7), (2, 3), (2, 4), (2, 6), (2, 9), (2, 13), (2, 18), (3, 4),
> (3, 5), (3, 6), (3, 7), (3, 8), (3, 9), (3, 11), (3, 12), (3, 14), (3,
> 16), (4, 5), (4, 7), (4, 11), (4, 12), (5, 10), (6, 8), (6, 10), (7,
> 10), (7, 14), (7, 15), (7, 16), (7, 17), (9, 13), (9, 15), (9, 17),
> (9, 19), (11, 14), (11, 15), (11, 16), (11, 17), (11, 18), (12, 13),
> (15, 19), (15, 18), (16, 19)]
> >>> n3 = G.neighbors(3)
> >>> n3
> [0, 1, 2, 4, 5, 6, 7, 8, 9, 11, 12, 14, 16]
> >>> n4 = G.neighbors(4)
> >>> n4
> [0, 2, 3, 5, 7, 11, 12]
> >>> sn34 = set(n3).intersection(set(n4))
> >>> n34 = list(sn34)
> >>> n34
> [0, 2, 5, 7, 11, 12]
> >>> n34.extend([3,4])
> >>> n34
> [0, 2, 5, 7, 11, 12, 3, 4]
> >>> H = G.subgraph(n34)
> >>> H.nodes()
> [0, 2, 3, 4, 5, 7, 11, 12]
> >>> H.edges()
> [(0, 12), (0, 3), (0, 4), (0, 5), (2, 3), (2, 4), (3, 4), (3, 5), (3,
> 7), (3, 11), (3, 12), (4, 5), (4, 7), (4, 11), (4, 12)]
> >>> nx.density(H)
> 0.5357142857142857
>
> Next, how to find the corresponding 2-alter-alter network:
>
> >>> H.remove_nodes_from([3,4])
> >>> H.nodes()
> [0, 2, 5, 7, 11, 12]
> >>> H.edges()
> [(0, 12), (0, 5)]
> >>> nx.density(H)
> 0.13333333333333333
>
> Best,
>
> --Moses
>
> On Sat, Feb 22, 2014 at 1:15 AM, Jesse Sayles <[log in to unmask]>
> wrote:
> > ***** To join INSNA, visit http://www.insna.org *****
> > Hi Socnet users,
> >
> > Would anyone know how to extract an ego-neighborhood for two nodes in the
> > SNA R package?
> >
> > I know that ego.extract will allow me to extract ego neighborhoods for
> > specific nodes, but I want to extract the combined neighborhood for two
> > nodes (that is all nodes connected to nodes 3 or 4, for example).
> >
> > I then need to calculate size, density, and centralization on each
> extracted
> > ego neighborhood. For these measures,  I need to exclude the focal nodes.
> > Can I exclude the focal nodes from the resulting ego network when using
> > ego.extract?
> >
> > Thank you
> > Jesse
> >
> > --
> >
> > Jesse Sayles
> > PhD candidate
> > School of Geographical Sciences & Urban Planning
> > Arizona State University
> > geoplan.asu.edu/sayles
> >
> >
> >
> > Graduate Assistant Fellow
> > Rob and Melani Walton Sustainability Solutions Initiatives
> > sustainabilitysolutions.asu.edu/programs/fellowships/?pid=7689
> >
> >
> > _____________________________________________________________________
> SOCNET
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> > [log in to unmask] containing the line UNSUBSCRIBE SOCNET in the
> body of
> > the message.
>



-- 

Jesse Sayles
PhD candidate
School of Geographical Sciences & Urban Planning
Arizona State University
geoplan.asu.edu/sayles



Graduate Assistant Fellow

Rob and Melani Walton Sustainability Solutions Initiatives
sustainabilitysolutions.asu.edu/programs/fellowships/?pid=7689

_____________________________________________________________________
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