rev {base}R Documentation

Reverse Elements

Description

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

To obtain a vector sorted in decreasing order efficiently, use sort(x, decreasing = TRUE), not rev(sort(x)).

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.

See Also

seq, sort.

Examples

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

[Package base version 4.5.2 Index]