Checks for lists and composite objects

Checks for composite objects. See chk_atomic for scalar and vector types, and chk_other for various other checks.

Function	Passes when
chk_environment(x)	x is an environment
chk_list(x)	x is a list, and carries no class
chk_data_frame(x)	x is a data.frame of sound structure
chk_data_table(x)	x is also a data.table
chk_tibble(x)	x is also a tbl_df

Usage

chk_environment(x, ..., null.ok = FALSE, contains = character())

chk_list(x, ..., null.ok = FALSE, attr.ok = "names", length = NULL)

chk_data_frame(x, ..., null.ok = FALSE)

chk_data_table(x, ..., null.ok = FALSE)

chk_tibble(x, ..., null.ok = FALSE)

Arguments

x

Object to check.

...

These dots are for future extensions and must be empty.

null.ok

Is NULL permitted?

contains

Character vector of names that must be bound in the environment. Applies to chk_environment().

attr.ok

Which attributes x may carry beyond those intrinsic to its type: a character vector of permitted attribute names, FALSE for none at all, or TRUE for any. Applies to chk_list().

length

Permitted length. NULL for any length, a scalar for one exact length, or a vector whose first and last elements give the minimum and the maximum. Neither may be negative, and NA at an end, or Inf as the maximum, means no bound there.

Value

The original object if the check passes.

See also

chk_atomic for the scalar and vector types, and chk_other for classes, conditions, and the rlang aliases.

Examples

chk_data_frame(mtcars)
chk_list(list(a = 1, b = 2), length = 2)

# chk_list() only accepts bare (unclassed) lists
tryCatch(chk_list(mtcars), error = wrap_error)
#> #E> Assertion on `mtcars` failed: • Must be
#> #E> of type 'list', not 'data.frame' • Must
#> #E> not have a class attribute, but has class
#> #E> "data.frame" • Must not have attributes:
#> #E> row.names