R: Check if an argument is a list

checkList {checkmate} | R Documentation

## Check if an argument is a list

### Description

Check if an argument is a list

### Usage

    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 only missing values allowed? Default is `TRUE`.
`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`.
`...` | [any] Additional parameters used in a call of `checkVector`.

### 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` returns a string with the error message. The function `expect_list` always returns an `expectation`.

### See Also

Other basetypes: `checkArray`, `checkAtomic`, `checkCharacter`, `checkComplex`, `checkDataFrame`, `checkDate`, `checkEnvironment`, `checkFactor`, `checkFunction`, `checkIntegerish`, `checkInteger`, `checkLogical`, `checkMatrix`, `checkNull`, `checkNumeric`, `checkVector`

### Examples

    testList(list())
    testList(as.list(iris), types = c("numeric", "factor"))

[Package checkmate version 1.8.2 Index]