evaluating string variables

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of 
Leonardo Sepulveda Dur??n
Sent: Friday, August 12, 2005 7:44 AM
To: r-help at stat.math.ethz.ch
Subject: [R] evaluating string variables

Hello!!!

I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)

#define data frame
L <- data.frame(frame=numeric(7), L=numeric(7))
f0<-1/(5*(5-1)) # first variable for computation

#loop over matrices, Open it , calculate property and put 
into data frame
for(i in 0:6){
	m<-matrix(scan('C:/R/i.mat', n=5*5),5,5, byrow=TRUE) # 
load matrix
	f1<-geodist(m)                                          
                 
	f2<-sum(colSums(f1$gdist))                              
          
	l <-f0*f2                                               
             
       # Calculate property
	L[i+1, ]<-c(i,l)                                        
             
      # Fill data frame
}

but the matrix cannot be loaded, because it try to open a file named
"i.mat". I don`t know how to loop with a counter named 'i', and use it
to define the name of the file too. How can i do it? I have not found
the way.
 
Leonardo