I have a dataframe with a column indicating choices (of a survey) as well as a column indicating the index of the choice made in each row. e.g.,
df <- tibble(
record_id = 1:9,
choices = c(rep("1, A | 2, B | 3, C", 3),
rep("1, Apple | 2, Banana | 3, Cherry", 3),
rep("1, America | 2, Belgium | 3, China", 3)),
choice = sample(1:3, size = 9, replace = T)
)
Which looks like this:
# A tibble: 9 × 3
record_id choices choice
<int> <chr> <int>
1 1 1, A | 2, B | 3, C 3
2 2 1, A | 2, B | 3, C 2
3 3 1, A | 2, B | 3, C 3
4 4 1, Apple | 2, Banana | 3, Cherry 3
5 5 1, Apple | 2, Banana | 3, Cherry 3
6 6 1, Apple | 2, Banana | 3, Cherry 2
7 7 1, America | 2, Belgium | 3, China 2
8 8 1, America | 2, Belgium | 3, China 3
9 9 1, America | 2, Belgium | 3, China 3
I would like to create a column recoding the choice by the label indicated in the choices column. e.g.,:
# A tibble: 9 × 3
record_id choices choice label
<int> <chr> <int> <chr>
1 1 1, A | 2, B | 3, C 3 C
2 2 1, A | 2, B | 3, C 2 B
3 3 1, A | 2, B | 3, C 3 C
4 4 1, Apple | 2, Banana | 3, Cherry 3 Cherry
5 5 1, Apple | 2, Banana | 3, Cherry 3 Cherry
6 6 1, Apple | 2, Banana | 3, Cherry 2 Banana
7 7 1, America | 2, Belgium | 3, China 2 Belgium
8 8 1, America | 2, Belgium | 3, China 3 China
9 9 1, America | 2, Belgium | 3, China 3 China
So far I've created a function to recode a choice, but it doesn't work in a pipe to mutate:
make_key <- function(.str) {
lstr <- str_split(.str, pattern = " \\| ")
out <- map(lstr, ~str_remove(.x, pattern = "^([0-9]+), ")) %>% as_vector()
out_names <- map(lstr, ~str_extract(.x, pattern = "^([0-9]+)")) %>% as_vector()
names(out) <- out_names
return(out)
}
# Working example:
my_string <- c("1, A | 2, B | 3, C")
recode(1, !!!make_key(my_string))
[1] "A"
But when I try to use it in a call to dplyr::mutate(), it doesn't work. I think it has something to do with passing a variable name to a function but not sure how.
rowwise(df) %>%
mutate(label = recode(choice, !!!make_key(choices))
)
Error in stri_split_regex(string, pattern, n = n, simplify = simplify, :
object 'choices' not found
I have tried adding double braces {{}} to lstr <- str_split({{.str}}, pattern = " \\| "), as well as some rlang functions to deal with the problem, e.g., .str <- rlang::as_name(.str) or .str <- rlang::enquo(.str), but so far nothing has worked.
what about:
library(dplyr)
pick_label <- \(choices, choice){
frags <- unlist(strsplit(choices, ' \\| '))
frags[grepl(paste0('^', choice), frags)] |>
gsub(pattern = '^.*, *', replacement = '')
}
df |>
rowwise() |>
mutate(label = pick_label(choices, choice))
\(x) is a shorthand for function(x) in R 4.1 and higher