Compute ordinal scores from continuous data

ordinal_scores.R

## Author Martin Papenberg
## Year 2018 

## This code is released into the public domain. Anybody may use, alter
## and distribute the code without restriction. The author makes no
## guarantees, and takes no liability of any kind for use of this code.

#' Compute ordinal scores from continuous data
#'
#' Might be useful for data exploration with highly skewed data
#' (e.g. having outliers). As this leads to a loss in information,
#' it should be used with caution.
#'
#' @param x A numeric vector
#' @param groups How many different scores should be computed (2 leads
#'     to a median split).
#' @param na.rm logical; if true, any ‘NA’ and ‘NaN’'s are removed from
#'     ‘x’ before the scores are computed.
#'
#' @return A vector a of length `length(x)` where each data point
#'     represents the ordinal score.

ordinal_scores <- function(x, groups, na.rm = FALSE) {
    probs <- seq(0, 1, length.out=groups+1)
    quants <- quantile(x, probs, na.rm)
    quant_scores <- vector(length=length(x))
    for (i in length(quants):2) {
        quant_scores <- ifelse(x <= quants[i], i, quant_scores)
    }
    return(quant_scores-1)
}