logical | 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. In numeric and complex vectors, zeros are `FALSE`

and
non-zero values are `TRUE`

.
For `factor`

s, 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.
Logical operators are documented in `Logic`

.

## non-zero values are TRUE as.logical(c(pi,0)) if (length(letters)) cat("26 is TRUE\n") ## logical interpretation of particular strings charvec <- c("FALSE", "F", "False", "false", "fAlse", "0", "TRUE", "T", "True", "true", "tRue", "1") as.logical(charvec) ## factors are converted via their levels, so string conversion is used as.logical(factor(charvec)) as.logical(factor(c(0,1))) # "0" and "1" give NA

What can we improve?

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.

Close