Group by columns and summarize a column into a list

Question

I have a dataframe like this:

sample_df<-data.frame(
   client=c(\'John\', \'John\',\'Mary\',\'Mary\'),
   date=c(\'2016-07-13\',\'2016-07-13\',\'2016-07         


        

Answer 1

We can use toString to concat the unique elements in 'cluster' together after grouping by 'client'

r1 <- sample_df %>% 
         group_by(client, date) %>%
         summarise(cluster = toString(unique(cluster)))

Or another option would be to create a list column

r2 <- sample_df %>%
         group_by(client, date) %>% 
         summarise(cluster = list(unique(cluster)))

which we can unnest

library(tidyr)
r2 %>%
    ungroup %>%
     unnest()