R: Integer Vectors (original) (raw)
| integer {base} | R Documentation |
|---|
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 \pm 2 \times 10^9: [double](../../base/help/double.html)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 toNA (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](../../base/help/trunc.html)(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 with0x or 0X) can be converted, as well as any allowed by the platform for real numbers. Like [as.vector](../../base/help/as.vector.html) it strips attributes including names. (To ensure that an object x is of integer type without stripping attributes, use[storage.mode](../../base/help/storage.mode.html)(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](../../base/help/round.html), as in the functionis.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
[numeric](../../base/help/numeric.html), [storage.mode](../../base/help/storage.mode.html).
[round](../../base/help/round.html) (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)
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 ...
[Package _base_ version 4.6.0 Index]