CODE EXAMPLE FOR R

how to create for loop through columns and count non na cells by group in r

library(dplyr)

d %>%
  group_by(ID) %>%
  summarise(across(Col1:Col3, ~ sum(!is.na(.x)), .names = "non-{.col}"))

# A tibble: 3 x 4
     ID `non-Col1` `non-Col2` `non-Col3`
  <dbl>      <int>      <int>      <int>
1     1          3          2          3
2     2          2          0          2
3     3          1          1          0