Re: [igraph] degree according to vertex attributes

[Dominik Santner (CRIE)]

Hello Tamás,

I just solved my problems:

I solved the first problem by simply adding an argument 
(delete.vertices=F) to subgraph.edges.

The second problem was solved this way (maybe its not the most elegant 
way, but it works):

To receive a graph with empty labels I exported it and reimported it 
immediately:

write.graph(xxx, "temp.net", format="pajek")
xxx2 <- read.graph("temp.net"´, format="pajek")

Then I added the city attribute of the original graph to my new graph:

V(xxx2)$st_AMR <- V(xxx)$st_AMR

And everything works fine!

Thank you very much for your previous help!

Best regards,

Dominik



Am 29.09.2012 11:56, schrieb Dominik Santner (CRIE):
> Hello,
>
> thank you very much for your suggestion. Unfortunately there are two 
> problems:
>
> first:
> when using your example graph created by
>
> > g <- grg.game(100, 0.2)
> > V(g)$city <- LETTERS[(0:99 %/% 10) + 1]
>
> I recieve a warning when doing
>
> > degree(g)-degree(internal.graph)
>
> telling me that the two objects are not of the same length
>
> > length(degree(internal.graph))
> [1] 96
> > length(degree(g))
> [1] 100
>
>
> the second problem occures when applying this procedure to my data:
>
> in your example you use V(g)$city when doing
>
> > internal.edges <- which(V(g)$city[el[,1]] == V(g)$city[el[,2]])
>
> whith the result:
> > internal.edges
>   [1]   1   5   6   7   8 ...
>
> when checking for
> > V(g)$city
>   [1] "A" "A" "A" "A" "A" ...
>
> > V(g)$city[el[,2]]
>   [1] "A" "B" "B" "B" "A" "A" ...
>
> everything is fine.
>
>
> But with my dataset this happens:
>
> > internal.edges <- which(V(xxx)$st_AMR[el[,1]] == V(xxx)$st_AMR[el[,2]])
> > internal.edges
> integer(0)
>
> > V(xxx)$st_AMR
>   [1] "München"                "Darmstadt" "Regensburg"             
> "Halle" ...
>
> > V(xxx)$st_AMR[el[,2]]
>   [1] NA NA NA NA NA ...
>
> Maybe it has something to do with my vertex labels and/or my edge 
> list, but I have no idea what it might be:
>
> The edge list of your example:
>
> > head(el)
>      [,1] [,2]
> [1,]    1    7
> [2,]    1   11
> [3,]    1   12
> [4,]    1   13
> [5,]    2    3
> [6,]    2    4
>
> The edge list of my dataset:
>
> > head(el)
>      [,1]
> [1,] "Company A (6411000)"
> [2,] "Company A (6411000)"
> [3,] "Company A (6411000)"
> [4,] "Company A (6411000)"
> [5,] "Company A (6411000)"
> [6,] "Company A (6411000)"
>      [,2]
> [1,] "University A (8416041)"
> [2,] "University B (8416041)"
> [3,] "Company B (5562024)"
> [4,] "Company C (5358024)"
> [5,] "Company D (5358024)"
> [6,] "Company E (8215101)"
>
> Best regards
> Dominik
>
>
> Am 28.09.2012 23:44, schrieb Tamás Nepusz:
> > Hello,
> >
> > Suppose that the city is encoded in the "city" vertex attribute of 
> > the graph; for instance:
> >
> > > g <- grg.game(100, 0.2)
> > > V(g)$city <- LETTERS[(0:99 %/% 10) + 1]
> > First, we get the edge list of the graph:
> >
> > > el <- get.edgelist(g)
> > Next, we select those edges (i.e. rows) from the edge list where the 
> > endpoints are in the same city:
> >
> > > internal.edges <- which(V(g)$city[el[,1]] == V(g)$city[el[,2]])
> > We then create a subgraph which consists of these edges only:
> >
> > > internal.graph <- subgraph.edges(g, internal.edges)
> > degree(internal.graph) will then give you how many friends each 
> > person has in the same city, and degree(g)-degree(internal.graph) 
> > will give you how many friends each person has in different cities.
> >
> > Best,