logical {base}

R Documentation

Logical Vectors

Description

Create or test for objects of type "logical", and the basic logical “constants”.

Usage

TRUE
FALSE
T; F

logical(length = 0)
as.logical(x, ...)
is.logical(x)

Arguments

length	desired length.
x	object to be coerced or tested.
...	further arguments passed to or from other methods.

Details

TRUE and FALSE are part of the R language, where T and F are global variables set to these. All four are logical(1) vectors.

is.logical is generic: you can write methods to handle of specific classes of objects, see InternalMethods.

Value

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) and not the codes. Like as.vector it strips attributes including names.

is.logical returns TRUE or FALSE depending on whether its argument is of logical type or not.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.

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