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## Re: [igraph] How to preserve E(g)

 From: Gabor Csardi Subject: Re: [igraph] How to preserve E(g) Date: Mon, 12 Nov 2007 10:16:26 +0100 User-agent: Mutt/1.5.13 (2006-08-11)

```Hmmm, I'm not completely sure what you want to do. If you want to save
the edge list with symbolic vertex names then you can use

get.edgelist(g)

Eg:

cbind(z, eBtw\$edge.betweenness,get.edgelist(g)[z+1,])

Note that you need to add 1 to the edge ids to index the matrix.
Is this what you need?

Gabor

On Mon, Nov 12, 2007 at 03:21:56PM +0900, MATSUDA, Noriyuki wrote:
> Hello:
>
>   Given a graph "g", E(g) gives an edge list on the console like
>        [0]  4a  -- 0A
>        [1]  5a  -- 0A
>             .......
>       [13] 17b -- 1B
>       [14] 18c -- 2C
> How can I keep the result in a variable, say "eg"?
>    What I really want to is to construct a matrix to store selected
> information of the edge.betweenness.community for later use.  I'd
> appreciate if some one can rescue me out of trouble shown below:
> -----------------------------------------------------------------------------------------------------------
> library(igraph); options(digits=3)
> # Naming vertices by sub-group
> eA<- c(0,4,0,5,0,6,0,7,0,8,0,9,0,10)
> eB<- c(1,11,1,12,1,13,1,14,1,15,1,16,1,17)
> eC<- c(2,18,2,19,2,20,2,21,2,22,2,23,2,24)
> eD<- c(3,25,3,26,3,27,3,28,3,29,3,30,3,31,3,32)
> g<-graph(c(eA,eB,eC,eD),directed=F)
> z <- 0:3;  V(g)[z]\$name = paste(V(g)[z],LETTERS[1:4],sep="")
> z <- 4:10; V(g)[z]\$name = paste(V(g)[z],"a",sep="")
> z <- 11:17; V(g)[z]\$name = paste(V(g)[z],"b",sep="")
> z <- 18:24; V(g)[z]\$name = paste(V(g)[z],"c",sep="")
> z <- 25:32; V(g)[z]\$name = paste(V(g)[z],"d",sep="")
>
> V(g)\$color="#efefef"; V(g)\$size=16
> V(g)[0:3]\$color="#aaaaFF"; V(g)[0:3]\$size=20
> E(g)\$color="black"
> V(g)[c(7,15,25)]\$color="#aabb99"
>
> quartz(width=7,height=7)
> plot(g, layout= layout.fruchterman.reingold.grid,vertex.label=V(g)\$name)
> title(main=list("fruchterman.reingold.grid",col="red",font=4,
> cex=1.2)) # 1=plain text, 2=bold face, 3=italic,  4=bold italic,
> 5=symbol
>
> #edge.betweenness.community removes the most outstanding edge, and
> repeats the process.
> #The results are hard to understand after the first removal
> eBtw <- edge.betweenness.community(g,merges=F)
> z <- eBtw\$removed.edges
> cbind(z, eBtw\$edge.betweenness,E(g)[z])
> ---------------------------------------------------------------------------------------------------------------
>
> --
> MATSUDA, Noriyuki　<in Kanji> 松 田 紀 之
>
>
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