[R] Random divisions

[Heidecker, Bettina]

I am working with microarray analysis and was using PAM with excel interface. Is there a way to do random divisions for the training set in excel? 
 
I also tried PAM in R with the pamr menu. How can I do the random divisions in R?  
 
 
Then I tried to reproduce "classification with gene expression data", which is chapter 24 from the book "bioinformatics and computational biology solutions using R and Bioconductor". There is also an explanation for random divisions using "eset" as an example. How do I have to load my data into R, to be able to reproduce, what they have done? what kind of file is eset? is it like an excel spreadsheet? I have my microarray data now in a .csv or .txt file with phenotype in the first row, class in the second row and then gene expression data starting from the third row. first column are the affy-IDs.  I have two classes. 
 
I would appreciate it, if someone could help me out with that!!!
Bettina