| logical {base} | R Documentation |
Create or test for objects of type "logical", and the basic
logical constants.
TRUE FALSE T; F logical(length = 0) as.logical(x, ...) is.logical(x)
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. |
TRUE and FALSE are reserved words denoting logical
constants in the R language, whereas T and F are global
variables whose initial values set to these. All four are
logical(1) vectors.
Logical vectors are coerced to integer vectors in contexts where a
numerical value is required, with TRUE being mapped to
1L, FALSE to 0L and NA to NA_integer_.
logical creates a logical vector of the specified length.
Each element of the vector is equal to FALSE.
as.logical attempts to coerce its argument to be of logical
type. For factors, this uses the levels
(labels). Like as.vector it strips attributes including
names. Character strings c("T", "TRUE", "True", "true") are
regarded as true, c("F", "FALSE", "False", "false") as false,
and all others as NA.
is.logical returns TRUE or FALSE depending on
whether its argument is of logical type or not.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
NA, the other logical constant.