Case when with condition loop

Question

I'm new on R. I wrote a case when code but I want to parametizer because not always I have n = 5. is it possible?

iris 
iris$id_1 = sample(1:10)
iris$id_2 = sample(1:10)
iris$id_3 = sample(1:10)
iris$id_4 = sample(1:10)
iris$id_5 = sample(1:10)

x = 3

iris <- 
  iris %>%
  mutate(
    segmento = 
      case_when(
        id_5 >= x ~ 5,
        id_4 >= x ~ 4,
        id_3 >= x ~ 3,
        id_2 >= x ~ 2,
        id_1 >= x ~ 1,
      )
  )

The problem is I have not always 5 "id". Sometimes I have 3 and the code It will be:

  iris <- 
      iris %>%
      mutate(
        segmento = 
          case_when(
            id_3 >= x ~ 3,
            id_2 >= x ~ 2,
            id_1 >= x ~ 1,
          )
      )

Then I need to parametizer it.

Thanks

Answer 1

Instead of using multiple case_when, based on the description, we can do (if we are comparing the number in the column name, extract that number with sub, do a comparison and get the column index with max.col on a logical matrix. Here, we specify last so that if we have a row with c(FALSE, TRUE, TRUE, TRUE), it gives the column index as 4

nm1 <- grep("^id_\\d+", names(df), value = TRUE)
max.col(df[nm1] >= as.numeric(sub("id_", "", nm1))[col(df[nm1])], "last")

---

Based on the updated post with 'iris' example

nm1 <- grep("^id_\\d+", names(iris), value = TRUE)
max.col(iris[nm1] >= x, "last")