The hardware and bandwidth for this mirror is donated by dogado GmbH, the Webhosting and Full Service-Cloud Provider. Check out our Wordpress Tutorial.
If you wish to report a bug, or if you are interested in having us mirror your free-software or open-source project, please feel free to contact us at mirror[@]dogado.de.

Variables labels and packed columns

Joseph Larmarange

The tidyr package allows to group several columns of a tibble into one single df-column, see tidyr::pack(). Such df-column is itself a tibble. It’s not currently clear why you would ever want to pack columns since few functions work with this sort of data.

library(tidyr)
d <- iris %>%
  as_tibble() %>%
  pack(
    Sepal = starts_with("Sepal"),
    Petal = starts_with("Petal"),
    .names_sep = "."
  )
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "Length of petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "Width of Petal"
class(d$Sepal)
## [1] "tbl_df"     "tbl"        "data.frame"

Regarding variable labels, you may want to define a label for one sub-column of a df-column, or eventually a label for the df-column itself.

For a sub-column, you could use easily var_label() to define your label.

library(labelled)
var_label(d$Sepal$Length) <- "Length of the sepal"
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "Length of petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "Width of Petal"

But you cannot use directly var_label() for the df-column.

var_label(d$Petal) <- "wrong label for Petal"
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"

As d$Petal is itself a tibble, applying var_label() on it would have an effect on each sub-column. To change a variable label to the df-column itself, you could use label_attribute().

label_attribute(d$Petal) <- "correct label for Petal"
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..- attr(*, "label")= chr "correct label for Petal"

On the other hand, set_variable_labels() works differently, as the primary intention of this function is to work on the columns of a tibble.

d <- d %>% set_variable_labels(Sepal = "Label of the Sepal df-column")
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##   ..- attr(*, "label")= chr "Label of the Sepal df-column"
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..- attr(*, "label")= chr "correct label for Petal"

This is equivalent to:

var_label(d) <- list(Sepal = "Label of the Sepal df-column")
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##   ..- attr(*, "label")= chr "Label of the Sepal df-column"
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "wrong label for Petal"
##   ..- attr(*, "label")= chr "correct label for Petal"

To use set_variable_labels() on sub-columns, you should use this syntax:

d$Petal <- d$Petal %>%
  set_variable_labels(
    Length = "Petal length",
    Width = "Petal width"
  )
str(d)
## tibble [150 × 3] (S3: tbl_df/tbl/data.frame)
##  $ Species: Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Sepal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##   .. ..- attr(*, "label")= chr "Length of the sepal"
##   ..$ Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##   ..- attr(*, "label")= chr "Label of the Sepal df-column"
##  $ Petal  : tibble [150 × 2] (S3: tbl_df/tbl/data.frame)
##   ..$ Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##   .. ..- attr(*, "label")= chr "Petal length"
##   ..$ Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##   .. ..- attr(*, "label")= chr "Petal width"
##   ..- attr(*, "label")= chr "correct label for Petal"

If you want to get the list of variable labels of a tibble, by default var_label() or get_variable_labels() will return the labels of the first level of columns.

d %>% get_variable_labels()
## $Species
## NULL
## 
## $Sepal
## [1] "Label of the Sepal df-column"
## 
## $Petal
## [1] "correct label for Petal"

To obtain the list of variable labels for sub-columns, you could use recurse = TRUE:

d %>% get_variable_labels(recurse = TRUE)
## $Species
## NULL
## 
## $Sepal
## $Sepal$Length
## [1] "Length of the sepal"
## 
## $Sepal$Width
## NULL
## 
## 
## $Petal
## $Petal$Length
## [1] "Petal length"
## 
## $Petal$Width
## [1] "Petal width"
d %>%
  get_variable_labels(
    recurse = TRUE,
    null_action = "fill",
    unlist = TRUE
  )
##               Species          Sepal.Length           Sepal.Width 
##             "Species" "Length of the sepal"               "Width" 
##          Petal.Length           Petal.Width 
##        "Petal length"         "Petal width"

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.