| 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
\pm 2 \times 10^9: doubles 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).
Like as.vector it strips attributes including names.
is.integer returns TRUE or FALSE depending on
whether its argument is of integer type or not.
is.integer is generic: you can write methods to handle
specific classes of objects, see InternalMethods.
There is a method for factors which returns FALSE.
(Prior to R 2.0.0, there was no such method and for most (but not
all) factors is.integer returned TRUE.)
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
## as.integer() truncates:
x <- pi * c(-1:1,10)
as.integer(x)