R: Last non-NA value among column sets

Question

I am looking for a solution to the problem below that would be supported in pipes.

I have data that looks like this:

tibble(
  column_set_1_1 = c(1, 2,         


        

Answer 1

Here is a solution that I came up with that works with pipes:

df_foo %>% 
  gather(key = Key, value = Value, -ID) %>% 
  mutate(set = str_extract(Key, "column_set_[0-9]")) %>% 
  mutate(number = str_extract(Key, "(?<=column_set_[0-9]_)[0-9]+")) %>% 
  group_by(ID, set) %>% 
  dplyr::filter(!is.na(Value)) %>%
  arrange(number) %>% 
  slice(n()) %>% 
  select(-number, -Key) %>% 
  spread(key = set, value = Value)

I don't like the fact that I have to arrange and then slice out the last row -- seems inelegant to me. Any improvements welcome.