Re: [igraph] question from a beginner

[Gábor Csárdi]

library(igraph)

data <- 

"AS3 AS6 AS10 AS1

AS56 AS23 AS36 AS1

AS123 AS568 AS2 AS45 AS36 AS1

AS79 AS1"

paths <- readLines(textConnection(data))

edges <- lapply(strsplit(paths, " "), function(x) {

  if (length(x)==2) {

    x

  } else {

    c(x[1], rep(x[2:(length(x)-1)], each=2), x[length(x)])

  }

})

G <- graph.edgelist(matrix(unlist(edges), ncol=2, byrow=TRUE))

str(G)

# IGRAPH DN-- 12 12 -- 

# + attr: name (v/c)

# + edges (vertex names):

#  [1] AS3  ->AS6   AS6  ->AS10  AS10 ->AS1   AS56 ->AS23  AS23 ->AS36 

#  [6] AS36 ->AS1   AS123->AS568 AS568->AS2   AS2  ->AS45  AS45 ->AS36 

# [11] AS36 ->AS1   AS79 ->AS1  

G.

On Tue, Mar 11, 2014 at 10:34 AM, Song Li <address@hidden> wrote:

I installed igraph in R, and i am also a beginner in R, could you give me a detail example for my question?

Thank you very much

Sky li

Hi,

in R? Python? C? 

Anyway, first create a long vector that contains the edges of your graph, and then use the regular igraph constructors, e.g. graph() in R.

Gabor

On Tue, Mar 11, 2014 at 10:25 AM, Song Li <address@hidden> wrote:

Hi everyone,

I'm a beginner in igraph. I have one simple question:

there is a file route.txt as below:

AS3 AS6 AS10 AS1
AS56 AS23 AS36 AS1
AS123 AS568 AS2 AS45 AS36 AS1
AS79 AS1

AS* represents a network node, and each line represents a route,for example: AS3->AS6->AS10->AS1 (line 1)

how to create a tree graph from this file?

Thanks!


Sky li

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