In R, why do I get Error in local_error_context(dots = dots, .index = i, mask = mask) when trying to-CodePudding

I have a dataset and a vector of column names that I want to apply within a while loop. I can write code so it will put the number of iterations in the column name (eg, n_1, n_2), but when I try to get it to pull the value (eg, a, b), I get various errors (detailed below).

Here's my sample dataset and what I want:

#set up
library(dplyr)
my_new_cols <- c("a", "b", "c")

current_data <- tibble(id = c(1:4),
                       score = c(10, 20, 30, 40))

#desired output
current_data <- tibble(id = c(1:4),
                       score = c(10, 20, 30, 40),
                       n_a = c("a 10", "a 20", "a 30", "a 40"),
                       n_b = c("b 10", "b 20", "b 30", "b 40"),
                       n_c = c("c 10", "c 20", "c 30", "c 40"))

And here are my many attempts. This first one runs, but instead of giving n_a, it gives n_1 (the index). It also weirdly gives column called 'n_`, and the output is a duplicate of n_3.

i = 1
while(i <= length(my_new_cols)) {
  current_data <- current_data %>%
    mutate("n_{{i}}" := paste(my_new_cols[i], score))
  i <- i  1
}

I also tried so many combinations calling in my_new_cols where you define column names, such as "n_{{my_new_cols[i]}}", "n_{{.data[i]}}", and "n_{{my_new_cols$i}}", all of which result in errors, most commonly

Error in local_error_context(dots = dots, .index = i, mask = mask) : promise already under evaluation: recursive default argument reference or earlier problems?

i = 1
while(i <= length(my_new_cols)) {
  current_data <- current_data %>%
    mutate("n_{{my_new_cols[i]}}" := paste(my_new_cols[i], score))
  i <- i  1
}

What's going on and how do I get the value rather than the index to show?

CodePudding user response：

If you change "n_{{my_new_cols[i]}}" to "n_{my_new_cols[i]}" your code works as expected.

i = 1
while(i <= length(my_new_cols)) {
  current_data <- current_data %>%
    mutate("n_{my_new_cols[i]}" := paste(my_new_cols[i], score))
  i <- i  1
}

Or try using a for loop instead, as the code is easier to understand.

for(i in my_new_cols) {
  current_data <- current_data %>%
    mutate("n_{i}" := paste(i, score))
}