R/cc.R

In mice: Multivariate Imputation by Chained Equations

#' Select complete cases
#'
#' Extracts the complete cases, also known as \emph{listwise deletion}.
#' \code{cc(x)} is similar to
#' \code{na.omit(x)}, but returns an object of the same class
#' as the input data. Dimensions are not dropped. For extracting
#' incomplete cases, use \code{\link{ici}}.
#'
#' @param x An \code{R} object. Methods are available for classes
#' \code{mids}, \code{data.frame} and \code{matrix}. Also, \code{x}
#' could be a vector.
#' @return A \code{vector}, \code{matrix} or \code{data.frame} containing the data of the complete cases.
#' @author Stef van Buuren, 2017.
#' @seealso \code{\link{na.omit}}, \code{\link{cci}}, \code{\link{ici}}
#' @keywords univar
#' @examples
#'
#' # cc(nhanes)   # get the 13 complete cases
#' # cc(nhanes$bmi) # extract complete bmi
#' @export
cc <- function(x) UseMethod("cc", x)

#' @export
cc.mids <- function(x) {
  x$data[cci(x), , drop = FALSE]
}

#' @export
cc.matrix <- function(x) {
  x[cci(x), , drop = FALSE]
}

#' @export
cc.data.frame <- function(x) {
  x[cci(x), , drop = FALSE]
}

#' @export
cc.default <- function(x) {
  x[cci(x)]
}


#' Select incomplete cases
#'
#' Extracts incomplete cases from a data set.
#' The companion function for selecting the complete cases is \code{\link{cc}}.
#'
#' @param x An \code{R} object. Methods are available for classes
#' \code{mids}, \code{data.frame} and \code{matrix}. Also, \code{x}
#' could be a vector.
#' @return A \code{vector}, \code{matrix} or \code{data.frame} containing the data of the complete cases.
#' @author Stef van Buuren, 2017.
#' @seealso \code{\link{cc}}, \code{\link{ici}}
#' @keywords univar
#' @examples
#'
#' ic(nhanes) # get the 12 rows with incomplete cases
#' ic(nhanes[1:10, ]) # incomplete cases within the first ten rows
#' ic(nhanes[, c("bmi", "hyp")]) # restrict extraction to variables bmi and hyp
#' @export
ic <- function(x) UseMethod("ic", x)

#' @export
ic.mids <- function(x) {
  x$data[ici(x), , drop = FALSE]
}

#' @export
ic.matrix <- function(x) {
  x[ici(x), , drop = FALSE]
}

#' @export
ic.data.frame <- function(x) {
  x[ici(x), , drop = FALSE]
}

#' @export
ic.default <- function(x) {
  x[ici(x)]
}