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Validate Every Element of a List

Source: R/compose.R
require_each.Rd

Applies a validator to each element of a list: list arguments, list-columns, collected ..., configuration lists. Errors carry the element path, layers[[2]] for unnamed elements and layers$key for named ones.

Usage

require_each(restriction, validator)

Arguments

restriction

a restriction object.

validator

a restriction object applied to every element.

Value

The modified restriction object.

Details

The value must be a list. An empty list passes. In fail-first mode the first invalid element stops the check; with .on_fail = "all" every failing element is reported.

See also

Other composition: allow_null(), require_any(), require_col(), require_fields(), require_valid()

Examples

layer <- restrict("layer") |> require_class("data.frame")
layers_v <- restrict("layers") |> require_class("list") |> require_each(layer)
layers_v(list(data.frame(a = 1), data.frame(b = 2)))
try(layers_v(list(data.frame(a = 1), "oops")))
#> Error : layers[[2]]: must be of class "data.frame", got character