integer {base} R Documentation

## Integer Vectors

### Description

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

### Usage

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

### Arguments

 `length` desired length. `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 on almost all implementations of R 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 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 is of integer type without stripping attributes, use `storage.mode`.)
`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.

`numeric`, `storage.mode`.
`round` (and `ceiling` and `floor` on that help page) to convert to integral values.
```  ## as.integer() truncates: