R/extract_data.R

In ShanEllis/phenopredict: Predicting phenotypes from RNA-seq expression data

#' Extracts data for predictions using regions from select_region()
#'
#' This function extracts regions of interest from data set on which you want
#' to make predictions.
#'
#' @param newexpression expression data set from which to extract coverage data
#' \code{expression}
#' @param newregiondata GRanges object containing region info
#' for expression data \code{newregiondata}
#' @param predictordata object output from build_predictor \code{predictordata}
#'
#' @return  covmat_test An n x m data.frame of the selected regions from the
#' data set specified by `expression`
#'
#' @keywords phenotype, prediction, data set
#'
#' @export
#'
#' @examples
#'
#' library('GenomicRanges')
#' library('dplyr')
#'
#' ## Make up some some region data
#' regions <- GRanges(seqnames = 'chr2', IRanges(
#'      start = c(28971710:28971712, 29555081:29555083, 29754982:29754984),
#'      end = c(29462417:29462419, 29923338:29923340, 29917714:29917716)))
#'
#' ## make up some expression data for 9 rows and 30 people
#' data(sysdata, package='phenopredict')
#' ## includes R object 'cm'
#' exp= cm[1:length(regions),1:30]
#'
#' ## generate some phenotype information
#' sex = as.data.frame(rep(c("male","female"),each=15))
#' age = as.data.frame(sample(1:100,30))
#' pheno = dplyr::bind_cols(sex,age)
#' colnames(pheno) <- c("sex","age")
#'
#' ## select regions to be used to build the predictor
#' inputdata <- filter_regions(expression=exp, regiondata=regions,
#' 	phenodata=pheno, phenotype="sex",
#' 	covariates=NULL,type="factor", numRegions=2)
#'
#' ## build phenotype predictor
#' predictor<-build_predictor(inputdata=inputdata ,phenodata=pheno,
#' 	phenotype="sex", covariates=NULL,type="factor", numRegions=2)
#'
#' ## determine resubstitution error
#' ## carry out prediction in training data set
#' predictions_test<-test_predictor(inputdata=inputdata ,phenodata=pheno,
#' 	phenotype="sex", covariates=NULL,type="factor",predictordata=predictor)
#'
#' ## generate new expressiondata set for prediction
#' exp_new= cm_new[1:length(regions),1:30]
#' ## extract test data
#' test_data<-extract_data(newexpression=exp_new,
#' newregiondata=predictor$regiondata, predictordata=predictor)

extract_data <- function(newexpression=NULL, newregiondata=NULL,
                         predictordata=NULL){
  # requireNamespace('plyr', quietly=TRUE)
  ##########
  ### Get the unique regions
  ### from the GTEX selection proces
  ##########
  requireNamespace('GenomicRanges', quietly=TRUE)
  requireNamespace('S4Vectors', quietly=TRUE)
  # first, some checks
  ##ADD thes
  if(is.null(newexpression)) {
    stop('Expression Data must be supplied.')
  }
  if(is.null(newregiondata)) {
    stop('Must specify genomic region information to use.')
  }
  if(is.null(predictordata)) {
    stop('Must specify predictor data to use. This is the
			output from build_predictor()')
  }

  # define function to extract regions when more
  # than one input file supplied
  # getexp <- function(x,y){
  # 				out<-x[y$regioninfo$index,]
  # 				return(out)
  # 			}

  sites <- GenomicRanges::findOverlaps(predictordata$regiondata, newregiondata)
  covmat_test = newexpression[S4Vectors::subjectHits(sites),]
  regiondata_test = newregiondata[S4Vectors::subjectHits(sites)]

  #if covmat is only one region, make sure it's still
  ## correct format and samples are in columns with regions in rows
  if(length(sites)==1){
    covmat_test = as.data.frame(t(covmat_test))
  }

  res <- list(covmat=covmat_test, regiondata=regiondata_test)
  return(res)
}