R: Tests whether an object is a vector or not

isNumericAtomicVector {splus2R} | R Documentation

## Tests whether an object is a vector or not

### Description

The `is.vector` function returns a `FALSE` value in some cases where intuitively one might expect a `TRUE` value to be returned. For example, `is.vector(z)` returns `FALSE` for each of the following:

i

  `z <- 1:3;names(z) <- 1:3`

ii

  `z <- matrix(1:3, nrow=1)`

iii

  `z <- matrix(1:3, ncol=1)`

These results are not necessarily incorrect, they are just one interpretion of the definition of a vector. Contrarily, the `isNumericAtomicVector(z)` function returns `TRUE` for each of the above examples. Thus, `isNumericAtomicVector` expands the basic definition of a vector to allow matrices containing a single row or column and named vectors. Also, unlike `is.vector`, `isNumericAtomicVector` returns `FALSE` for objects of class `list`.

### Usage

    isNumericAtomicVector(x)

### Arguments

`x` | an object of arbitrary class.

### Value

a vector of character strings containing the result. The length of this vector is equal to `length(x)`.

### Examples

    ## cases where isNumericAtomicVector returns
    ## TRUE
    z <- 1:3;names(z) <- letters[1:3]
    isNumericAtomicVector(z)
    isNumericAtomicVector(matrix(1:3, nrow=1))
    isNumericAtomicVector(matrix(1:3, ncol=1))
    isNumericAtomicVector(1:5)
    isNumericAtomicVector(letters)

    ## cases where isNumericAtomicVector returns
    ## FALSE
    isNumericAtomicVector(list(1:3))
    isNumericAtomicVector(data.frame(1:3,2:4))
    isNumericAtomicVector(matrix(1:12, nrow=4))

[Package splus2R version 1.3-3 Index]