Require a Specific Class

Validates that the value belongs to a given class. One verb covers the types without a dedicated check, including factor, Date, POSIXct, list, matrix, environment, and fitted-model objects such as lm.

Usage

require_class(restriction, class, exact = FALSE)

Arguments

restriction

a restriction object.

class

character(1) class name to require.

exact

logical; if TRUE, requires class(value)[1] to equal class exactly. If FALSE (default), tests inheritance with inherits(), so a subclass passes.

Value

The modified restriction object.

Details

A matrix is require_class("matrix") (inherits() is TRUE for matrices since R 4.0) and an environment is require_class("environment"); neither needs a dedicated step. Use require_dim() for the shape.

See also

Other type checks: require_character(), require_df(), require_integer(), require_logical(), require_numeric()

Examples

restrict("d") |> require_class("Date")
#> <restriction d>
#>   1. must be of class "Date"
restrict("f") |> require_class("factor")
#> <restriction f>
#>   1. must be of class "factor"
restrict("model") |> require_class("lm")
#> <restriction model>
#>   1. must be of class "lm"
restrict("m") |> require_class("matrix") |> require_dim(c(NA, 3))
#> <restriction m>
#>   1. must be of class "matrix"
#>   2. must have dim (any, 3)