dplyr n_distinct with condition

Question

Using dplyr to summarise a dataset, I want to call n_distinct to count the number of unique occurrences in a column. However, I also want to do another summarise() for all uniqu

Answer 1

Filtering the dataframe before performing the summarise works

a %>%
  filter(B=="Y") %>%
  summarise(count = n_distinct(A))