replace_na: Replace NA with specific values

Description

This function replaces (tagged) NA's of a variable, data frame or list of variables with value.

Usage

replace_na(x, ..., value, na.label = NULL, tagged.na = NULL)

Value

x, where NA's are replaced with value. If x

is a data frame, the complete data frame x will be returned, with replaced NA's for variables specified in ...; if ... is not specified, applies to all variables in the data frame.

Arguments

x: A vector or data frame.
...: Optional, unquoted names of variables that should be selected for further processing. Required, if x is a data frame (and no vector) and only selected variables from x should be processed. You may also use functions like : or tidyselect's select-helpers. See 'Examples' or package-vignette.
value: Value that will replace the NA's.
na.label: Optional character vector, used to label the the former NA-value (i.e. adding a labels attribute for value to x).
tagged.na: Optional single character, specifies a tagged_na value that will be replaced by value. Herewith it is possible to replace only specific NA values of x.

Details

While regular NA values can only be completely replaced with a single value, tagged_na allows to differentiate between different qualitative values of NAs. 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"). Therewith it is possible to replace only specific NA values, while other NA values are preserved.

Examples

Run this code

library(sjlabelled)
data(efc)
table(efc$e42dep, useNA = "always")
table(replace_na(efc$e42dep, value = 99), useNA = "always")

# the original labels
get_labels(replace_na(efc$e42dep, value = 99))
# NA becomes "99", and is labelled as "former NA"
get_labels(
  replace_na(efc$e42dep, value = 99, na.label = "former NA"),
  values = "p"
)

dummy <- data.frame(
  v1 = efc$c82cop1,
  v2 = efc$c83cop2,
  v3 = efc$c84cop3
)
# show original distribution
lapply(dummy, table, useNA = "always")
# show variables, NA's replaced with 99
lapply(replace_na(dummy, v2, v3, value = 99), table, useNA = "always")

if (require("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")))
  # get current NA values
  x
  get_na(x)

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

  table(x)
  table(replace_na(x, value = 2, tagged.na = "c"))

  # tagged NA also works for non-labelled class
  # init vector
  x <- c(1, 2, 3, 4)
  # set values 2 and 3 as tagged NA
  x <- set_na(x, na = c(2, 3), as.tag = TRUE)
  # see result
  x
  # now replace only NA tagged with 2 with value 5
  replace_na(x, value = 5, tagged.na = "2")
}