| numeric {base} | R Documentation |
Creates or tests for objects of type "numeric".
numeric(length = 0) as.numeric(x, ...) is.numeric(x)
length |
desired length. |
x |
object to be coerced or tested. |
... |
further arguments passed to or from other methods. |
as.numeric is a generic function, but methods must be
written for as.double, which it calls.
is.numeric is generic: you can write methods to handle
specific classes of objects, see InternalMethods.
Note that factors are false for is.numeric since there is a
"factor" method.
numeric creates a real vector of the specified length. The
elements of the vector are all equal to 0.
as.numeric attempts to coerce its argument to a numeric type
(either integer or real).
as.numeric for factors yields the codes underlying the factor
levels, not the numeric representation of the labels.
is.numeric returns TRUE if its argument is of
mode "numeric" (type "double" or type
"integer") and not a factor, and FALSE otherwise.
R has no single precision data type. All real numbers are stored in double precision format.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
as.numeric(c("-.1"," 2.7 ","B")) # (-0.1, 2.7, NA) + warning
as.numeric(factor(5:10))