R/coalesce_na.R

In kimisc: Kirill's miscellaneous functions

#' @title Replaces NA values
#' @description This (vectorized) function returns the first 
#'   non-\code{NA} argument, similar to the SQL function 
#'   \code{COALESCE}. If a vector or matrix is passed as first argument,
#'   the remaining arguments are recycled to generate a vector/matrix of
#'   the same dimension, and coalescing is done element by element.
#' @param x The first value to coalesce.
#' @param ... Other values to coalesce.
#' @return A vector of the same length as \code{x}.
#' @examples
#' coalesce.na(NA, -1)
#' coalesce.na(5, 3)
#' coalesce.na(c(1,NA,NA), c(NA,2))
#' coalesce.na(matrix(c(NA, 1:3), nrow=2))
#' coalesce.na(NA)
#' @export
coalesce.na <- function(x, ...) {
  x.len <- length(x)
  ly <- list(...)
  for (y in ly) {
    y.len <- length(y)
    if (y.len == 1) {
      x[is.na(x)] <- y
    } else {
      if (x.len %% y.len != 0)
        warning('object length is not a multiple of first object length')
      pos <- which(is.na(x))
      x[pos] <- y[(pos - 1) %% y.len + 1]
    }
  }
  x
}