R help - Apr 2003 - Social Network Analysis and R

I'm interested in computing densities of a number of small ego-centred or
local
networks. I've installed both the R program and the sna package.  My next
task
is importing the data into R. 

Our data was entered into Spss in an edgelist format in which each case 
specifies the link between an alter and an ego. For example: 

10101  10102  1 
10101  10103  3 
10102  10104  2 
10201  10203  4 
10203  10204  2 

The following data fragment for example shows an ego-centred network of 2 
persons: 101 and 102. Person 101 for example reports of a closeness of ties 
between alters 01 and 02 = value of 1; alters 01 and 03 - value of 3, etc. 
Similarly Person 102 reports on the closeness of ties between his alters 01 
and 03 = value of 4; and alters 03 and 04=value of 2. 

We have about 350 of these small ego networks represented as 560 cases in 
edgelist format in spss (each line or ego-alter relational link represents a 
case in spss). 

First, how do I write out the commands in R to read the edgelists ? 

Secondly, is there any way to tell R that the first 3 characters of the ego 
and alter values are actually identifiers for the ego networks -- so that 
densities are computed for each these? 

I've begun reading the reference manual on data reading and import
facilities
and hope that would help me get further along. 

thanks in advance - em 

--------------------------------------------------------
Emmanuel F. Koku               emmanuel.koku at utoronto.ca
          Doctoral Candidate - Sociology
          Centre for Urban and Community Studies
             University of Toronto
          455 Spadina Avenue, Toronto, Canada M5S 2G8
Tel: +1-416-425-4936           Fax: +1-416-425-7803

                 NOTE: Effective February 1. 2003
          New email address: emmanuel.koku at utoronto.ca

Emmanuel F. Koku wrote:
> I'm interested in computing densities of a number of small ego-centred
or local
> networks. I've installed both the R program and the sna package.  My
next task
> is importing the data into R. 
> 
> Our data was entered into Spss in an edgelist format in which each case 
> specifies the link between an alter and an ego. For example: 
> 
> 10101  10102  1 
> 10101  10103  3 
> 10102  10104  2 
> 10201  10203  4 
> 10203  10204  2 
> 
> The following data fragment for example shows an ego-centred network of 2 
> persons: 101 and 102. Person 101 for example reports of a closeness of ties
> between alters 01 and 02 = value of 1; alters 01 and 03 - value of 3, etc. 
> Similarly Person 102 reports on the closeness of ties between his alters 01
> and 03 = value of 4; and alters 03 and 04=value of 2. 
> 
> We have about 350 of these small ego networks represented as 560 cases in 
> edgelist format in spss (each line or ego-alter relational link represents
a
> case in spss). 
> 
> First, how do I write out the commands in R to read the edgelists ? 
> 
> Secondly, is there any way to tell R that the first 3 characters of the ego
> and alter values are actually identifiers for the ego networks -- so that 
> densities are computed for each these? 
> 
> I've begun reading the reference manual on data reading and import
facilities
> and hope that would help me get further along. 
[The question arises why you did not finish it before asking.]

See ?read.fwf for importing the data.

Uwe Ligges