Rev {DescTools}

Reverse Elements of a Vector, a Matrix, a Table, an Array or a Data.frame

Description

Rev provides a reversed version of its argument. Unlike the basic function, it does in higher-dimensional structures such as matrices not reverse the elements, but the order of the rows and/or columns. It further offers additional interfaces for higher dimensional arrays or tables.

Usage

Rev(x, ...)

## S3 method for class 'matrix'
Rev(x, margin, ...)

## S3 method for class 'table'
Rev(x, margin, ...)

## S3 method for class 'array'
Rev(x, margin, ...)

## S3 method for class 'data.frame'
Rev(x, margin, ...)

Arguments

x

a vector, a matrix or a higher dimensional table to be reversed.

margin

vector of dimensions which to be reversed (1 for rows, 2 for columns, etc.). If not defined, all dimensions will be reverted.

...

the dots are passed to the array interface.

Author(s)

Andri Signorell <[e-mail]>

See Also

rev, order, sort, seq

Examples

tab <- matrix(c(1, 11, 111,
                2, 22, 222,
                3, 33, 333), 
              byrow=TRUE, nrow=3,
              dimnames=list(mar1=1:3, mar2=c("a","b","c")))

Rev(tab, margin=1)
Rev(tab, margin=2)

# reverse both dimensions
Rev(tab, margin=c(1, 2))

t(tab)

# reverse 3dimensional array
aa <- Abind(tab, 2 * tab, along=3)
dimnames(aa)[[3]] <- c("A","Z")

# reverse rows
Rev(aa, 1)
# reverse columns
Rev(aa, 2)
# reverse 3th dimension
Rev(aa, 3)

# reverse all dimensions
Rev(aa)
# same as
Rev(aa, margin=(1:3))