R/splitByFactor.R

In PeteHaitch/RUVcorr: Removal of unwanted variation for gene-gene correlations and related analysis.

#' Splitting a data set by a particular factor.
#'
#' Internal function that splits a data set according to a particular factor.
#' 
#' @param X  A matrix containing gene expressions.
#' @param anno A dataframe or a matrix containing the annotation of arrays in \code{X}.
#' @param Factor A character string corresponding to a column name of \code{anno} to be used for splitting. 
#' @return \code{splitByFactor} returns a list object.
#' @keywords internal
#' @author Saskia Freytag
#' @export
splitByFactor<-function(X,
						anno, 
						Factor
						){
						
	expression<-list()
	col.num<-which(colnames(anno)==Factor)
	categories<-sort(unique(anno[,col.num]))
	ind<-lapply(categories, function(x) which(anno[,col.num]==x))
	expression<-lapply(ind, function(x) X[x,])
	names(expression)<-categories
	return(expression)
	
}