R/qcut.R

In stackcon/rngt: General data science and utilities package

#' Bin a numeric vector by quantiles
#'
#' @param x numeric vector
#' @param nbreaks number of 'quantile' bins to return. defaults to 4
#' @param ... other arguments passed to cut
#'
#' @return quantile factor-vector the same size as x
#' @importFrom stats quantile
#' @export
#'
#' @examples
#' qcut(runif(100), 10, ordered_result = TRUE)
qcut <- function(x, nbreaks, ...){
	retval = NULL
	qargs = alist(x, na.rm=TRUE)
	if(!missing(nbreaks))
		qargs$probs = seq(0,1, length.out = (nbreaks+1) )
	breaks = do.call(quantile, qargs)
	retval = cut(x, breaks, include.lowest = TRUE, ...)
	return(retval)
}

#' @describeIn qcut use bins that each span an equal portion of the range
#' @export
rangecut <- function(x, nbreaks, ...){

	stopifnot(is.numeric(nbreaks),
				 is.finite(nbreaks))

	if(length(nbreaks) > 1){
		warning("nbreaks has multiple elements; only using the first value here")
		nbreaks = nbreaks[1]
	}

	if(nbreaks %% 1 != 0){
		warning("rounding nbreaks down to nearest whole number")
		nbreaks = as.integer(nbreaks)
	}
	stopifnot(nbreaks > 0)
	# (NB -> just use cut(x, nbreaks,))
	#xrng = range(x, na.rm=T)
	#cut(x, seq(xrng[1], xrng[2], length.out = (nbreaks+1)), include.lowest = T, ...)
	return( cut(x, nbreaks, include.lowest = TRUE, ...) )
}