Reverse Elements of a Vector, a Matrix, a Table, an Array or a Data.frame
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.
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, ...)
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. |
Andri Signorell <andri@signorell.net>
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))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.