R: label variables based on their prefix - r

Question

Im new to R and trying to label multiple but not all variables of my data at the same time. Specifically, I want to label the variables starting with "pol". I tried to combine the select and the set_variable_labels command in the following manner:
cp14 <- cp14 %>%
select(matches("pol")) %>%
set_variable_labels(cp14,
labels = "Interest in politics")
I would like all variables that include "pol" to be labelled as "Interest in politics". This however does not work. Any advice on how to do this in a similar or completely different manner is greatly appreciated.
My data looks something like this, but with many more variables:
structure(list(pol_interest_w1 = c(0.5, 0.5, 0.25, 0.25, 0.25,
0.5), pol_interest_w2 = c(0.5, 0.5, 0.25, NA, 0.25, 0.5), pol_interest_w3 = c(0.5,
0.5, 0.25, NA, 0, 0.5), pol_interest_w4 = c(0.5, 0.5, 0.25, NA,
0, 0.5), pol_interest_w5 = c(0.5, 0.5, 0.25, NA, 0, 0.5), pol_interest_w6 = c(0.5,
0.5, 0.25, NA, 0, 0.5), pol_interest_w7 = c(0.5, 0.5, 0.25, NA,
0.25, 0.5), new_col = c(0.75, 0.5, 0.25, NA, 0.25, 0.5)), row.names = c(NA,
-6L), class = c("tbl_df", "tbl", "data.frame"))

Answer 1

You can do this in a couple ways. For either solution, start by creating a vector of variable names starting with "pol". (I use stringr::str_starts() here; you don’t want to use select(), as in your code, which is for subsetting columns from your dataset.)
library(stringr)
library(labelled)
pol_vars <- names(cp14)[str_starts(names(cp14), "pol")]
Then, you can make a named list of labels, and pass it to the .labels argument of labelled::set_variable_labels().
pol_labels <- setNames(
as.list(rep("Interest in politics", length(pol_vars))),
pol_vars
)
cp14 <- set_variable_labels(cp14, .labels = pol_labels)
Alternatively, you could loop over the variable names and assign labels using labelled::var_label().
for (v in pol_vars) {
var_label(cp14[[v]]) <- "Interest in politics"
}
Both approaches yield the same result:
#> var_label(cp14)
$pol_interest_w1
[1] "Interest in politics"
$pol_interest_w2
[1] "Interest in politics"
$pol_interest_w3
[1] "Interest in politics"
$pol_interest_w4
[1] "Interest in politics"
$pol_interest_w5
[1] "Interest in politics"
$pol_interest_w6
[1] "Interest in politics"
$pol_interest_w7
[1] "Interest in politics"
$new_col
NULL