Convert a vector of values to a prose list

prose-vector.r

##' Converts a vector of values to a formatted prose list
##'
##' @param vals a vector of values
##' @param oxford a boolean indicating whether Oxford comma should be used
##' @param and word before ultimate entry
##' @return a character string
prose_vector <- function(vals, oxford=FALSE, and="and") {
    if (length(vals)>1) {
        start <- head(vals, -1)
        start <- paste0(start, collapse=", ")
        end <- tail(vals, 1)
        return(paste0(start, ifelse(oxford, ", ", " "), and, " ", end))
    } else {
        return(vals)
    }
}