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Retrieve tagged NA values of labelled variables

Source: R/get_na.R
get_na.Rd

This function retrieves tagged NA values and their associated value labels from a labelled vector.

Usage

get_na(x, as.tag = FALSE)

Arguments

x

Variable (vector) with value label attributes, including tagged missing values (see tagged_na()); or a data frame or list with such variables.

as.tag

Logical, if TRUE, the returned values are not tagged NA's, but their string representative including the tag value. See 'Examples'.

Value

The tagged missing values and their associated value labels from x, or NULL if x has no tagged missing values.

Details

Other statistical software packages (like 'SPSS' or 'SAS') allow to define multiple missing values, e.g. not applicable, refused answer or "real" missing. These missing types may be assigned with different values, so it is possible to distinguish between these missing types. In R, multiple declared missings cannot be represented in a similar way with the regular missing values. However, tagged_na() values can do this. Tagged NAs work exactly like regular R missing values except that they store one additional byte of information: a tag, which is usually a letter ("a" to "z") or character number ("0" to "9"). This allows to indicate different missings.

Furthermore, see 'Details' in get_values.

Examples

library(haven)
#> Error in library(haven): there is no package called ‘haven’
x <- labelled(c(1:3, tagged_na("a", "c", "z"), 4:1),
              c("Agreement" = 1, "Disagreement" = 4, "First" = tagged_na("c"),
                "Refused" = tagged_na("a"), "Not home" = tagged_na("z")))
#> Error in labelled(c(1:3, tagged_na("a", "c", "z"), 4:1), c(Agreement = 1,     Disagreement = 4, First = tagged_na("c"), Refused = tagged_na("a"),     `Not home` = tagged_na("z"))): could not find function "labelled"
# get current NA values
x
#> Error: object 'x' not found
get_na(x)
#> Error: object 'x' not found
# which NA has which tag?
get_na(x, as.tag = TRUE)
#> Error: object 'x' not found

# replace only the NA, which is tagged as NA(c)
if (require("sjmisc")) {
  replace_na(x, value = 2, tagged.na = "c")
  get_na(replace_na(x, value = 2, tagged.na = "c"))

  # data frame as input
  y <- labelled(c(2:3, 3:1, tagged_na("y"), 4:1),
                c("Agreement" = 1, "Disagreement" = 4, "Why" = tagged_na("y")))
  get_na(data.frame(x, y))
}
#> Loading required package: sjmisc
#> Warning: there is no package called ‘sjmisc’