Copy variable and value labels and SPSS-style missing value

This function copies variable and value labels (including missing values) from one vector to another or from one data frame to another data frame. For data frame, labels are copied according to variable names, and only if variables are the same type in both data frames.

Usage

copy_labels(from, to, .strict = TRUE)

copy_labels_from(to, from, .strict = TRUE)

Arguments

from: A vector or a data.frame (or tibble) to copy labels from.
to: A vector or data.frame (or tibble) to copy labels to.
.strict: When from is a labelled vector, to have to be of the same type (numeric or character) in order to copy value labels and SPSS-style missing values. If this is not the case and .strict = TRUE, an error will be produced. If .strict = FALSE, only variable label will be copied.

Details

Some base R functions like base::subset() drop variable and value labels attached to a variable. copy_labels could be used to restore these attributes.

copy_labels_from is intended to be used with dplyr syntax, see examples.

Examples

library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union
df <- tibble(
  id = 1:3,
  happy = factor(c("yes", "no", "yes")),
  gender = labelled(c(1, 1, 2), c(female = 1, male = 2))
) %>%
  set_variable_labels(
    id = "Individual ID",
    happy = "Are you happy?",
    gender = "Gender of respondent"
  )
var_label(df)
#> $id
#> [1] "Individual ID"
#> 
#> $happy
#> [1] "Are you happy?"
#> 
#> $gender
#> [1] "Gender of respondent"
#> 
fdf <- df %>% filter(id < 3)
var_label(fdf) # some variable labels have been lost
#> $id
#> [1] "Individual ID"
#> 
#> $happy
#> [1] "Are you happy?"
#> 
#> $gender
#> [1] "Gender of respondent"
#> 
fdf <- fdf %>% copy_labels_from(df)
var_label(fdf)
#> $id
#> [1] "Individual ID"
#> 
#> $happy
#> [1] "Are you happy?"
#> 
#> $gender
#> [1] "Gender of respondent"
#> 

# Alternative syntax
fdf <- subset(df, id < 3)
fdf <- copy_labels(from = df, to = fdf)