Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

47 lines (45 sloc) 1.618 kb
#' Order a data frame by its colums.
#'
#' This function completes the subsetting, transforming and ordering triad
#' with a function that works in a similar way to \code{\link{subset}} and
#' \code{\link{transform}} but for reordering a data frame by its columns.
#' This saves a lot of typing!
#'
#' @param df data frame to reorder
#' @param ... expressions evaluated in the context of \code{df} and then fed
#' to \code{\link{order}}
#' @keywords manip
#' @seealso \code{\link{order}} for sorting function in the base package
#' @export
#' @examples
#' # sort mtcars data by cylinder and displacement
#' mtcars[with(mtcars, order(cyl, disp)), ]
#' # Same result using arrange: no need to use with(), as the context is implicit
#' # NOTE: plyr functions do NOT preserve row.names
#' arrange(mtcars, cyl, disp)
#' # Let's keep the row.names in this example
#' myCars = cbind(vehicle=row.names(mtcars), mtcars)
#' arrange(myCars, cyl, disp)
#' # Sort with displacement in descending order
#' arrange(myCars, cyl, desc(disp))
arrange <- function(df, ...) {
ord <- eval(substitute(order(...)), df, parent.frame())
if(length(ord) != nrow(df)) {
stop("Length of ordering vectors don't match data frame size",
call. = FALSE)
}
unrowname(df[ord, , drop = FALSE])
}
#' Descending order.
#'
#' Transform a vector into a format that will be sorted in descending order.
#'
#' @param x vector to transform
#' @keywords manip
#' @export
#' @examples
#' desc(1:10)
#' desc(factor(letters))
#' first_day <- seq(as.Date("1910/1/1"), as.Date("1920/1/1"), "years")
#' desc(first_day)
desc <- function(x) -xtfrm(x)
Jump to Line
Something went wrong with that request. Please try again.