How to use Dplyr's Summarize and which() to lookup min/max values

Question

I have the following data:

Name <- c(\"Sam\", \"Sarah\", \"Jim\", \"Fred\", \"James\", \"Sally\", \"Andrew\", \"John\", \"Mairin\", \"Kate\", \"Sasha\", \         


        

Answer 1

You can use which.min and which.max to get the first value.

data %>% group_by(Group) %>%
  summarize(minAge = min(Age), minAgeName = Name[which.min(Age)], 
            maxAge = max(Age), maxAgeName = Name[which.max(Age)])

To get all values, use e.g. paste with an appropriate collapse argument.

data %>% group_by(Group) %>%
  summarize(minAge = min(Age), minAgeName = paste(Name[which(Age == min(Age))], collapse = ", "), 
            maxAge = max(Age), maxAgeName = paste(Name[which(Age == max(Age))], collapse = ", "))