Check if an argument is a list

Check if an argument is a list

checkList(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE
)

check_list(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE
)

assertList(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE,
  .var.name = vname(x),
  add = NULL
)

assert_list(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE,
  .var.name = vname(x),
  add = NULL
)

testList(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE
)

test_list(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE
)

expect_list(
  x,
  types = character(0L),
  any.missing = TRUE,
  all.missing = TRUE,
  len = NULL,
  min.len = NULL,
  max.len = NULL,
  unique = FALSE,
  names = NULL,
  null.ok = FALSE,
  info = NULL,
  label = vname(x)
)

Arguments

x

[any]
Object to check.

types

[character]
Character vector of class names. Each list element must inherit from at least one of the provided types. The types “logical”, “integer”, “integerish”, “double”, “numeric”, “complex”, “character”, “factor”, “atomic”, “vector” “atomicvector”, “array”, “matrix”, “list”, “function”, “environment” and “null” are supported. For other types inherits is used as a fallback to check x's inheritance. Defaults to character(0) (no check).

any.missing

[logical(1)]
Are vectors with missing values allowed? Default is TRUE.

all.missing

[logical(1)]
Are vectors with no non-missing values allowed? Default is TRUE. Note that empty vectors do not have non-missing values.

len

[integer(1)]
Exact expected length of x.

min.len

[integer(1)]
Minimal length of x.

max.len

[integer(1)]
Maximal length of x.

unique

[logical(1)]
Must all values be unique? Default is FALSE.

names

[character(1)]
Check for names. See checkNamed for possible values. Default is “any” which performs no check at all. Note that you can use checkSubset to check for a specific set of names.

null.ok

[logical(1)]
If set to TRUE, x may also be NULL. In this case only a type check of x is performed, all additional checks are disabled.

.var.name

[character(1)]
Name of the checked object to print in assertions. Defaults to the heuristic implemented in vname.

add

[AssertCollection]
Collection to store assertion messages. See AssertCollection.

info

[character(1)]
Extra information to be included in the message for the testthat reporter. See expect_that.

label

[character(1)]
Name of the checked object to print in messages. Defaults to the heuristic implemented in vname.

Value

Depending on the function prefix: If the check is successful, the functions

assertList/assert_list return

x invisibly, whereas

checkList/check_list and

testList/test_list return

TRUE. If the check is not successful,

assertList/assert_list

throws an error message,

testList/test_list

returns FALSE, and checkList/check_list

return a string with the error message. The function expect_list always returns an

expectation.

Note

Contrary to R's is.list, objects of type data.frame and pairlist are not recognized as list.

Missingness is defined here as elements of the list being NULL, analogously to anyMissing.

The test for uniqueness does differentiate between the different NA types which are built-in in R. This is required to be consistent with unique while checking scalar missing values. Also see the example.

See also

Other basetypes: checkArray(), checkAtomicVector(), checkAtomic(), checkCharacter(), checkComplex(), checkDataFrame(), checkDate(), checkDouble(), checkEnvironment(), checkFactor(), checkFormula(), checkFunction(), checkIntegerish(), checkInteger(), checkLogical(), checkMatrix(), checkNull(), checkNumeric(), checkPOSIXct(), checkRaw(), checkVector()

Examples

testList(list())
#> [1] TRUE
testList(as.list(iris), types = c("numeric", "factor"))
#> [1] TRUE

# Missingness
testList(list(1, NA), any.missing = FALSE)
#> [1] TRUE
testList(list(1, NULL), any.missing = FALSE)
#> [1] FALSE

# Uniqueness differentiates between different NA types:
testList(list(NA, NA), unique = TRUE)
#> [1] FALSE
testList(list(NA, NA_real_), unique = TRUE)
#> [1] TRUE