# integer

##### Integer Vectors

Creates or tests for objects of type `"integer"`

.

- Keywords
- classes

##### Usage

```
integer(length = 0)
as.integer(x, ...)
is.integer(x)
```

##### Arguments

- length
- A non-negative integer specifying the desired length. Double values will be coerced to integer: supplying an argument of length other than one is an error.
- x
- object to be coerced or tested.
- ...
- further arguments passed to or from other methods.

##### Details

Integer vectors exist so that data can be passed to C or Fortran code which expects them, and so that (small) integer data can be represented exactly and compactly.

Note that current implementations of R use 32-bit integers for
integer vectors, so the range of representable integers is restricted
to about $+/-2*10^9$: `double`

s can
hold much larger integers exactly.

##### Value

`integer`

creates a integer vector of the specified length.
Each element of the vector is equal to `0`

.`as.integer`

attempts to coerce its argument to be of integer
type. The answer will be `NA`

unless the coercion succeeds. Real
values larger in modulus than the largest integer are coerced to
`NA`

(unlike S which gives the most extreme integer of the same
sign). Non-integral numeric values are truncated towards zero (i.e.,
`as.integer(x)`

equals `trunc(x)`

there), and
imaginary parts of complex numbers are discarded (with a warning).
Character strings containing optional whitespace followed by either a
decimal representation or a hexadecimal representation (starting with
`0x`

or `0X`

) can be converted, as well as any allowed by
the platform for real numbers. Like `as.vector`

it strips
attributes including names. (To ensure that an object `x`

is of
integer type without stripping attributes, use
`storage.mode(x) <- "integer"`

.)`is.integer`

returns `TRUE`

or `FALSE`

depending on
whether its argument is of integer type or not, unless it is a
factor when it returns `FALSE`

.
##### Note

`is.integer(x)`

does **not** test if `x`

contains integer
numbers! For that, use `round`

, as in the function
`is.wholenumber(x)`

in the examples.

##### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.

##### See Also

`round`

(and `ceiling`

and `floor`

on that help
page) to convert to integral values.

##### Examples

`library(base)`

```
## as.integer() truncates:
x <- pi * c(-1:1, 10)
as.integer(x)
is.integer(1) # is FALSE !
is.wholenumber <-
function(x, tol = .Machine$double.eps^0.5) abs(x - round(x)) < tol
is.wholenumber(1) # is TRUE
(x <- seq(1, 5, by = 0.5) )
is.wholenumber( x ) #--> TRUE FALSE TRUE ...
```

*Documentation reproduced from package base, version 3.1.3, License: Part of R 3.1.3*