Get / Set a variable label

Get / Set a variable label

var_label(x, unlist = FALSE)

var_label(x) <- value

set_variable_labels(.data, ..., .labels = NA, .strict = TRUE)

Arguments

x

a vector or a data.frame

unlist

for data frames, return a named vector instead of a list

value

a character string or NULL to remove the label For data frames, it could also be a named list or a character vector of same length as the number of columns in x.

.data

a data frame

...

name-value pairs of variable labels (see examples)

.labels

variable labels to be applied to the data.frame, using the same syntax as value in var_label(df) <- value.

.strict

should an error be returned if some labels doesn't correspond to a column of x?

Value

set_variable_labels() will return an updated copy of .data.

Details

For data frames, if value is a named list, only elements whose name will match a column of the data frame will be taken into account. If value is a character vector, labels should in the same order as the columns of the data.frame.

Note

set_variable_labels() could be used with dplyr syntax.

Examples

var_label(iris$Sepal.Length)
#> NULL
var_label(iris$Sepal.Length) <- 'Length of the sepal'
if (FALSE) {
 View(iris)
}
# To remove a variable label
var_label(iris$Sepal.Length) <- NULL
# To change several variable labels at once
var_label(iris) <- c(
  "sepal length", "sepal width", "petal length",
  "petal width", "species"
)
var_label(iris)
#> $Sepal.Length
#> [1] "sepal length"
#> 
#> $Sepal.Width
#> [1] "sepal width"
#> 
#> $Petal.Length
#> [1] "petal length"
#> 
#> $Petal.Width
#> [1] "petal width"
#> 
#> $Species
#> [1] "species"
#> 
var_label(iris) <- list(
  Petal.Width = "width of the petal",
  Petal.Length = "length of the petal"
)
var_label(iris)
#> $Sepal.Length
#> [1] "sepal length"
#> 
#> $Sepal.Width
#> [1] "sepal width"
#> 
#> $Petal.Length
#> [1] "length of the petal"
#> 
#> $Petal.Width
#> [1] "width of the petal"
#> 
#> $Species
#> [1] "species"
#> 
var_label(iris, unlist = TRUE)
#>          Sepal.Length           Sepal.Width          Petal.Length 
#>        "sepal length"         "sepal width" "length of the petal" 
#>           Petal.Width               Species 
#>  "width of the petal"             "species" 

if (require(dplyr)) {
  # adding some variable labels
  df <- tibble(s1 = c("M", "M", "F"), s2 = c(1, 1, 2)) %>%
    set_variable_labels(s1 = "Sex", s2 = "Yes or No?")
  var_label(df)

  # removing a variable label
  df <- df %>% set_variable_labels(s2 = NULL)
  var_label(df$s2)

  # Set labels from dictionary, e.g. as read from external file
  # One description is missing, one has no match
  description = tibble(
    name = c(
      "Sepal.Length", "Sepal.Width", "Petal.Length", "Petal.Width",
      "Something"),
    label = c(
      "Sepal length", "Sepal width",  "Petal length", "Petal width",
      "something")
  )
  var_labels <- setNames(as.list(description$label), description$name)
  iris_labelled <- iris %>%
    set_variable_labels(.labels = var_labels, .strict = FALSE)
  var_label(iris_labelled)

  # defining variable labels derived from variable names
  if (require(snakecase)) {
    iris <- iris %>%
      set_variable_labels(.labels = to_sentence_case(names(iris)))
    var_label(iris)
  }
}
#> Loading required package: snakecase
#> $Sepal.Length
#> [1] "Sepal length"
#> 
#> $Sepal.Width
#> [1] "Sepal width"
#> 
#> $Petal.Length
#> [1] "Petal length"
#> 
#> $Petal.Width
#> [1] "Petal width"
#> 
#> $Species
#> [1] "Species"
#>