arg_data: Check Common Argument Types

In arg: Clean and Simple Argument Checking

Check Common Argument Types

Description

Checks whether an argument is an atomic vector (arg_atomic()), a dimensionless atomic vector (arg_vector()), a list (arg_list()), a data frame (arg_data.frame()), a matrix (arg_matrix()), an array (arg_array()), a rectangular data set (arg_data()), or an environment (arg_env()).

Usage

arg_atomic(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_vector(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_list(x, df_ok = FALSE, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_data.frame(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_matrix(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_array(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_data(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_env(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

Arguments

x	the argument to be checked
.arg	the name of the argument supplied to x to appear in error messages. The default is to extract the argument's name using rlang::caller_arg(). Ignored if .msg is supplied.
.msg	an optional alternative message to display if an error is thrown instead of the default message.
.call	the execution environment of a currently running function, e.g. .call = rlang::current_env(). The corresponding function call is retrieved and mentioned in error messages as the source of the error. Passed to err(). Set to NULL to omit call information. The default is to search along the call stack for the first user-facing function in another package, if any.
df_ok	logical; whether to allow data frames (which are technically lists). Default is FALSE to throw an error on a data frame input.

Details

Atomic vectors are checked using is.atomic(). Because matrices are considered atomic vectors, arg_vector() additionally checks that there is no "dims" attribute, i.e., that length(dim(x)) == 0L. arg_data() checks whether x is either a data frame or a matrix. arg_list() checks whether x is a list; when df = FALSE, it throws an error when x is a data frame, even though data frames are lists.

Value

Returns NULL invisibly if an error is not thrown.

See Also

is.atomic(), is.list(), is.data.frame(), is.matrix(), is.array(), is.environment(), arg_is()

Examples

vec <- 1:6
mat <- as.matrix(vec)
dat <- as.data.frame(mat)
lis <- as.list(vec)
nul <- NULL

# arg_atomic
try(arg_atomic(vec))
try(arg_atomic(mat))
try(arg_atomic(dat))
try(arg_atomic(lis))
try(arg_atomic(nul))

# arg_vector
try(arg_vector(vec))
try(arg_vector(mat))

# arg_matrix
try(arg_matrix(vec))
try(arg_matrix(mat))
try(arg_matrix(dat))

# arg_data.frame
try(arg_data.frame(vec))
try(arg_data.frame(mat))
try(arg_data.frame(dat))

# arg_data
try(arg_data(vec))
try(arg_data(mat))
try(arg_data(dat))

arg documentation built on April 9, 2026, 5:09 p.m.