xvalidate

#' My function for doing cross validation (creating the splits before hand)
xvalidate <- function(f, formula, data, bin, ...) {
  fold <- length(bin)
  xs <- seq.int(1, fold)

  lapply(xs, function(x) {
    train <- data[unlist(bin[-x]),]
    test <- data[bin[[x]],]

    model <- f(formula, data = train, ...)
    predict(model, newdata = test)
  })
}