R: Drop Redundant Extent Information

drop {base} | R Documentation

## Drop Redundant Extent Information

### Description

Delete the dimensions of an array which have only one level.

### Usage

    drop(x)

### Arguments

`x` | an array (including a matrix).

### Value

If `x` is an object with a `dim` attribute (e.g., a matrix or `array`), then `drop` returns an object like `x`, but with any extents of length one removed. Any accompanying `dimnames` attribute is adjusted and returned with `x`: if the result is a vector the `names` are taken from the `dimnames` (if any). If the result is a length-one vector, the names are taken from the first dimension with a dimname.

Array subsetting (`[`) performs this reduction unless used with `drop = FALSE`, but sometimes it is useful to invoke `drop` directly.

### See Also

`drop1` which is used for dropping terms in models.

### Examples

    dim(drop(array(1:12, dim = c(1,3,1,1,2,1,2)))) # = 3 2 2
    drop(1:3 %*% 2:4)  # scalar product

[Package base version 4.0.5 Index]