R/calc_var_groups.R

In iaradsouza1/MicroarrayMethods: Provide methods for microarray analysis

#' Calculate variance in defined groups
#'
#' @param exp_matrix An normalized expression matrix.
#' @param groups A factor with the experiment groups in the same order as it appears on the expression matrix.
#'
#' @return A data.frame with group variances
#' @export
#'
#' @examples
calc_var_groups <- function(exp_matrix, groups) {

  # Define groups
  groups <- split(1:ncol(exp_matrix), groups)

  # Calculate inner group variance
  temp1 <- sapply(groups, function(x) {
    apply(exp_matrix[, x], 1, var)
  })
  colnames(temp1) <- paste0(names(groups), ".Var")
  as.data.frame(temp1)

}