subtable {rje}

Subset an array

Description

More flexible calls of [ on an array.

Usage

subtable(x, variables, levels, drop = TRUE)

subarray(x, levels, drop = TRUE)

subtable(x, variables, levels) <- value

subarray(x, levels) <- value

Arguments

x

An array.

variables

An integer vector containing the dimensions of x to subset.

levels

A list or vector containing values to retain.

drop

Logical indicating whether dimensions with only 1 retained should be dropped. Defaults to TRUE.

value

Value to assign to entries in table.

Details

Essentially just allows more flexible calls of [ on an array.

subarray requires the values for each dimension should be specified, so for a 2 \times 2 \times 2 array x, subarray(x, list(1,2,1:2)) is just x[1,2,1:2].

subtable allows unspecified dimensions to be retained automatically. Thus, for example subtable(x, c(2,3), list(1, 1:2)) is x[,1,1:2].

Value

Returns an array of dimension sapply(value, length) if drop=TRUE, otherwise specified dimensions of size 1 are dropped. Dimensions which are unspecified in subtable are never dropped.

Functions

• subarray: Flexible subsetting

• subtable<-: Assignment in a table

• subarray<-: Assignment in an array

Author(s)

Mathias Drton, Robin Evans

See Also

Extract

Examples

x = array(1:8, rep(2,3))
subarray(x, c(2,1,2)) == x[2,1,2]

x[2,1:2,2,drop=FALSE]
subarray(x, list(2,1:2,2), drop=FALSE)

subtable(x, c(2,3), list(1, 1:2))