rev provides a reversed version of its argument. It is generic
function with a default method for vectors and one for
dendrograms.

Note that this is no longer needed (nor efficient) for obtaining
vectors sorted into descending order, since that is now rather more
directly achievable by sort(x, decreasing = TRUE).

Usage

rev(x)

Arguments

x

a vector or another object for which reversal is defined.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole.

x <- c(1:5, 5:3)
## sort into descending order; first more efficiently:stopifnot(sort(x, decreasing = TRUE) == rev(sort(x)))
stopifnot(rev(1:7) == 7:1) #- don't need 'rev' here