How to summarise unique values with respect to another coulmn?

General
7

The code would be something like this

library(lubridate)
library(dplyr)

r %>%
    mutate(date = dmy(date)) %>% 
    group_by(continent, location) %>% 
    filter(date == max(date)) %>% 
    group_by(continent) %>% 
    summarise(population = sum(population))

As I said before, If you need more specific help, please provide a proper REPR oducible EX ample (reprex) illustrating your issue.