Re: [R] Converting edgelist to symmetric matrix

From: Gary Weissman <gary_at_babelgraph.org>
Date: Mon, 11 Apr 2011 08:54:55 -0400

Hi Shafique,

If your edgelist is in the form of a text file (elist.csv) that looks like this:

from, to, weight

vertex1, vertex2, 3
vertex2, vertex3, 2.3
vertex4, vertex1, 1.2

...

you can convert that to a matrix using

library(igraph)

edge.list <- read.csv(elist.csv,header=TRUE)

g <- graph.data.frame(edge.list, directed=FALSE)

get.adjacency(g, type="both", attr="weight")

More options for exporting the adjacency matrix are here:

http://igraph.sourceforge.net/doc/R/conversion.html

If you give more details about your data format you might get more specific help.

HTH,
Gary

On Apr 11, 2011, at 6:00 AM, r-help-request_at_r-project.org wrote:

>
>
>
>
>
> ----------------------------------------

>> Date: Sat, 9 Apr 2011 14:34:28 -0700
>> From: kmshafique_at_yahoo.com
>> To: r-help_at_r-project.org
>> Subject: [R] Converting edgelist to symmetric matrix
>> 
>> Hi,
>> I have network data in the form of a couple of edgelists containing weights in
>> the format "x,y,weight" whereby x represents row header and y represents column
>> header. All edgelists are based on links among 634 nodes and I need to convert
>> them into a 634*634 weighted matrix.
>> 
>> 

>
> not find
>> a clue how to do this in R. Any help will be appreciated.

>
> I'm trying to do something related and found
>
> ?read.graph
>
> will format=ncol do what you need? This apparently creates a graph object that likely
> has capacilities you need.? Again, I haven't actually used any of this
> just found while trying to solve a different problem.
>
> 'It is a simple text file
> with one edge per line. An edge is defined by two symbolic vertex
> names separated by whitespace. (The symbolic vertex names
> themselves cannot contain whitespace. They might followed by an
> optional number, this will be the weight of the edge; the number
> can be negative and can be in scientific notation. If there is no
> weight specified to an edge it is assumed to be zero.
> '
>
>> 
>> Best regards,
>> Shafique
>> 

>
>
--
Gary Weissman
http://www.babelgraph.org/
gary_at_babelgraph.org




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