validate_that: Validate that certain conditions are true.

In assertthat: Easy Pre and Post Assertions

Description

validate_that is an alternative to the function assert_that, that returns a character vector. This makes them easier to use within S4 "validate" methods.

Usage

validate_that(..., env = parent.frame(), msg = NULL)

Arguments

...	unnamed expressions that describe the conditions to be tested. Rather than combining expressions with &&, separate them by commas so that better error messages can be generated.
env	(advanced use only) the environment in which to evaluate the assertions.
msg	a custom error message to be printed if one of the conditions is false.

Value

A character vector if the assertion is false, or TRUE if the assertion is true.

See Also

assert_that, which returns an error if the condition is false.

Examples

x <- 1
# assert_that() generates errors, so can't be usefully run in
# examples
validate_that(is.numeric(x))
validate_that(is.character(x))
validate_that(length(x) == 3)
validate_that(is.dir("asdf"))

Example output

[1] TRUE
[1] "x is not a character vector"
[1] "length(x) not equal to 3"
[1] "Path 'asdf' does not exist"

assertthat documentation built on May 1, 2019, 10:25 p.m.