Search code examples
rdplyrtidyversetidyeval

What is the alternative to deprecated SE dplyr verbs in a for loop?

I'm used to using the SE versions of dplyr verbs in for loops and am wanting to transition to the new evaluation semantics, but I'm struggling.

In older dplyr versions I would do something like:

df <- tribble(
  ~x, ~y, ~z,
  "a", 2, "dog",
  "b", 1, "cat",
  "a", 2,  "cat"
)

for (i in names(df %>% select(x,z))){
  print(count_(df,i))
}

# A tibble: 2 x 2
  x         n
  <chr> <int>
1 a         2
2 b         1
# A tibble: 2 x 2
  z         n
  <chr> <int>
1 cat       2
2 dog       1

I have tried various combinations of quo/enquo/!!/!!! and can't seem to make it work using count().

Solution

  • Use sym to turn the string into a symbol, then use !! to insert the symbol into the expression

    for (i in names(df %>% select(x,z))){
  print(count(df, !!sym(i)))
}