R: Converting array and vector Indices Calculate the vector...

array2vec {arrayhelpers} | R Documentation

## Converting array and vector Indices Calculate the vector index from array indices, and vice versa.

### Description

`array`s are `numeric`s with a `dim` attribute and are stored with the first index moving fastest (i.e. by column). They can be indexed both ways.

### Usage

    array2vec(iarr, dim)

    vec2array(ivec, dim)

### Arguments

`iarr` | vector with the indices into the array dimensions
`dim` | vector with the array dimensions, as returned by `dim (x)`
`ivec` | scalar with the index into the vector

### Value

`array2vec` returns a scalar, `vec2array` a `matrix`.

### Author(s)

C. Beleites

### See Also

see `Extract` on the difference of indexing an `array` with a vector or a `matrix`.

### Examples

    arr <- array (rnorm (24), dim = 2 : 4)
    arr

    v <- matrix(c(2, 2, 2), nrow = 1)
    i <- array2vec (v, dim = dim (arr))
    i
    arr[v]
    arr[i]

    arr[c(2, 2, 2)] ## indexing with a vector
    arr[2]

    i <- 14
    v <- vec2array (i, dim = dim (arr))
    v
    arr [v]
    arr [i]

[Package arrayhelpers version 1.0-20160527 Index]