R/pruneNets.R

In netDx: Network-based patient classifier

#' Prune interaction networks to keep only the networks and patients 
#' requested
#'
#' @details This function is crucial for patient data that is highly 
#' sparse; examples include patient CNVs indels, as opposed to full matrix
#' measures (gene expression, questionnaire data). Each step where the pool
#' of patients is subset - e.g. limiting feature selection only to patients
#' in training set - changes the set of networks that are eligible. 
#' Some networks may only contain test patients, while others may contain
#' a single edge between a training and a test patient. Upon subsetting,
#' such networks are no longer eligible for downstream use, such as 
#' feature selection. This function rewrites those subnetworks of the 
#' original networks that consist of eligible patients. 
#' @param oldDir (char) path to directory with original networks
#' @param newDir (char) path to output directory for pruned networks
#' @param filterNets (char) vector of networks to include. These should 
#' match filenames in \code{netDir}. Value of '*' results in pruning all
#' networks
#' @param filterIDs (char) patients to include in pruned networks. These
#' should match nodes in the input interaction networks
#' @param netSfx (char) suffix for network file names. Only used if 
#' \code{filterNets='*'}.
#' @param verbose (logical) print messages
#' @return (no value). Side effect of writing pruned network files to 
#' \code{newDir}
#' @examples
#' data(npheno)
#' netDir <- system.file("extdata","example_nets",package='netDx')
#' pruneNets(netDir,tempdir(),filterIDs=npheno[seq_len(10),],
#'  netSfx='txt$')
#' @export
pruneNets <- function(oldDir, newDir=tempdir(), 
		filterNets = "*", filterIDs = "*", 
		netSfx = "_cont.txt$", verbose = TRUE) {
    if (length(filterNets) == 1) {
        if (filterNets == "*") {
            if (verbose) 
                message("* Including all networks\n")
            fList <- dir(path = oldDir, pattern = netSfx)
            filterNets <- fList
        }
    }
    if (verbose) 
        message(sprintf("Limiting to %i networks\n", length(filterNets)))
    
    if (!file.exists(newDir)) 
        dir.create(newDir)
    
    if (length(filterIDs) == 1) {
        if (filterIDs == "*") {
            # keep all patients
            message("* Including all patients\n")
            for (f in filterNets) {
                oldf <- paste(oldDir,f,sep=getFileSep())
                newf <- paste(newDir,f,sep=getFileSep())
                file.copy(oldf, newf)
            }
        }
    } else {
        if (verbose) 
            message(sprintf("Limiting to %i patients\n", length(filterIDs)))
        for (f in filterNets) {
            dat <- read.delim(paste(oldDir,f,sep=getFileSep()), 
		sep = "\t", 
		header = FALSE, as.is = TRUE)
            
            # both nodes of edge should be eligible
            idx <- intersect(which(dat[, 1] %in% filterIDs), 
		which(dat[, 2] %in% filterIDs))
            
            write.table(dat[idx, ], file = paste(newDir,f,sep=getFileSep()),
		sep = "\t", col.names = FALSE, row.names = FALSE, 
		quote = FALSE)
        }
    }
}