R/cardinality.R

In stackcon/rngt: General data science and utilities package

#' Return unique values
#'
#' Function that returns the number of unique values in a particular vector
#'
#' @param x vector
#' @param ... additional arguments passed to `base::unique`
#'
#' @return number of unique values in the input vector
#' @export
n.unique <- function(x, ...){
	length(unique(x, ...))
}

#' Check if all values in a vector are the same
#'
#' @param xx A vector
#' @param na.rm should NA values be omitted
#' @param fail_if_na should function return FALSE when NA values are present
#' @param ... additional arguments passed to `base::unique`
#'
#' @return logical value indicating whether all values in the vector were equal
#' @importFrom stats na.omit
#' @export
#'
#' @examples
#' all_same( c(rep(0, 10), NA) )
#' all_same( c(rep(0, 10), NA), na.rm=TRUE )
#' all_same( rep(NA, 10) )
#' all_same( rep(NA, 10), na.rm=TRUE )
#' all_same( rep(NA, 10), na.rm=FALSE, fail_if_na=TRUE )
all_same = function(xx, na.rm = FALSE, fail_if_na = FALSE, ...){

	uu = unique(xx, ...)

	if( na.rm ){
		uu = na.omit(uu)
	} else if( any(is.na(uu)) ){
		if(fail_if_na){
			warning("Returned FALSE because of NA values")
			return(FALSE)
		} else if( length(uu) == 2 ){
			warning("all equal except for NA values. set `na.rm=TRUE` to exclude these")
		}
	}

	return( length(uu) == 1 )
}