# integer {base}

### Description

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

.

### 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.

### Values

`integer`

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

.

`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`

.

### References

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

### 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.

### Examples

## 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 R 3.0.2. License: GPL-2.