pad: Pad data

Description

Pre- or postpad the data object x with the value c until it is of length l.

Usage

pad(x, l, c = 0, MARGIN = 2, direction = c("both", "pre", "post"))
prepad(x, l, c = 0, MARGIN = 2)
postpad(x, l, c = 0, MARGIN = 2)

Value

Padded data, returned as a vector or matrix.

Arguments

x

Vector or matrix to be padded

l

Length of output data along the padding dimension. If length (x) > l, elements from the beginning (dimension = "pre") or the end (direction = "post") of x are removed until a vector of length l is obtained. If direction = "both", values are removed from both ends, and in case of an uneven length the smallest number of elements is removed from the beginning of vector.

c

Value to be used for the padding (scalar). Must be of the same type as the elements in x. Default: 0

MARGIN

A vector giving the subscripts which the function will be applied over. E.g., for a matrix 1 indicates rows, 2 indicates columns, c(1, 2) indicates rows and columns. Where x has named dimnames, it can be a character vector selecting dimension names. If MARGIN is larger than the dimensions of x, the result will have MARGIN dimensions. Default: 2 (columns).

direction

Where to pad the array along each dimension. One of the following:

"pre": Before the first element

"post"

After the last element

"both"

(default) Before the first and after the last element

Author

Geert van Boxtel, G.J.M.vanBoxtel@gmail.com.

Examples

Run this code

v <- 1:24
res <- postpad(v, 30)
res <- postpad(v, 20)
res <- prepad(v, 30)
res <- prepad(v, 20)

m <- matrix(1:24, 4, 6)
res <- postpad(m, 8, 100)
res <- postpad(m, 8, 100, MARGIN = 1)
res <- prepad(m, 8, 100)
res <- prepad(m, 8, 100, MARGIN = 1)

res <- postpad(m, 2)
res <- postpad(m, 2, MARGIN = 1)
res <- prepad(m, 2)
res <- prepad(m, 2, MARGIN = 1)