R/splitData.R

In stnava/itkImageR: Examples using Rcpp to interface R and ITK

splitData <- function(data.source, ratio, return.rows = FALSE) {
  if (ratio > 1) {
    split.cv <- TRUE
  } else {
    split.cv <- FALSE
  }
  nsubjects <- dim(data.source)[1]
  if (split.cv) {
    mylist <- list()
    fold.ids <- sample(nsubjects)%%round(ratio) + 1
    for (i in sort(unique(fold.ids))) {
      subjects.in <- (1:nsubjects)[fold.ids != i]
      subjects.out <- (1:nsubjects)[fold.ids == i]
      data.in <- data.source[subjects.in, ]
      data.out <- data.source[subjects.out, ]
      mylist[[paste("fold", i, sep = "")]] <- list(data.in = data.in, data.out = data.out)
      if (return.rows) {
        mylist[[paste("fold", i, sep = "")]] <- list(data.in = data.in, data.out = data.out, rows.in = subjects.in, 
          rows.out = subjects.out)
      }
    }
    return(mylist)
  } else if (!split.cv) {
    subjects.in <- sort(sample(nsubjects, ratio * nsubjects, replace = FALSE))
    data.in <- data.source[subjects.in, ]
    data.out <- data.source[-subjects.in, ]
    mylist <- list(data.in = data.in, data.out = data.out)
    if (return.rows) 
      mylist <- list(data.in = data.in, data.out = data.out, rows.in = subjects.in, rows.out = (1:nsubjects)[-subjects.in])
    return(mylist)
  }
}