pattern-matching / 'map_when' helper?

[kevinushey]

This would be something similar to case_when(), but for mapping conditions to operations -- something like a generalized switch.

As an example, the following code:

mtcars %>% map_when(
  starts_with("d") ~ prod(.),
  contains("a")    ~ sum(.),
  c("mpg", "cyl")  ~ cor(.)
)

would evaluate to something like:

> mtcars %>% map_when(
+   starts_with("d") ~ prod(.),
+   contains("a")    ~ sum(.),
+   c("mpg", "cyl")  ~ cor(.)
+ )
[[1]]
[1] 1.218225e+91

[[2]]
[1] 336.09

[[3]]
          mpg       cyl
mpg  1.000000 -0.852162
cyl -0.852162  1.000000

Would this be worth adding to rlang (or somewhere similar)? Or does this already exist as some function I'm not aware of?

[lionel-]

That might fit in the vctrs package, which will probably be the home of case_when() in the future.

[lionel-]

/move to vctrs

[lionel-]

and nothing happens :p where are you move bot?

[ghost]

This issue was moved by lionel- to r-lib/vctrs#66.