R: Check if an argument is a flag

checkFlag {checkmate} | R Documentation

## Check if an argument is a flag

### Description

A flag is defined as single logical value.

### Usage

    checkFlag(x, na.ok = FALSE, null.ok = FALSE)

    check_flag(x, na.ok = FALSE, null.ok = FALSE)

    assertFlag(x, na.ok = FALSE, null.ok = FALSE, .var.name = vname(x), add = NULL)

    assert_flag(
      x,
      na.ok = FALSE,
      null.ok = FALSE,
      .var.name = vname(x),
      add = NULL
    )

    testFlag(x, na.ok = FALSE, null.ok = FALSE)

    test_flag(x, na.ok = FALSE, null.ok = FALSE)

    expect_flag(x, na.ok = FALSE, null.ok = FALSE, info = NULL, label = vname(x))

### Arguments

`x` | [any] Object to check.
`na.ok` | [`logical(1)`] Are missing values allowed? Default is `FALSE`.
`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`.

### Details

This function does not distinguish between `NA`, `NA_integer_`, `NA_real_`, `NA_complex_` `NA_character_` and `NaN`.

### Value

Depending on the function prefix: If the check is successful, the functions `assertFlag`/`assert_flag` return `x` invisibly, whereas `checkFlag`/`check_flag` and `testFlag`/`test_flag` return `TRUE`. If the check is not successful, `assertFlag`/`assert_flag` throws an error message, `testFlag`/`test_flag` returns `FALSE`, and `checkFlag` returns a string with the error message. The function `expect_flag` always returns an `expectation`.

### See Also

Other scalars: `checkCount()`, `checkInt()`, `checkNumber()`, `checkScalarNA()`, `checkScalar()`, `checkString()`

### Examples

    testFlag(TRUE)
    testFlag(1)

[Package checkmate version 2.0.0 Index]