I would like to select a row with maximum value in each group with dplyr.
Firstly I generate some random data to show my question
df <- expand.grid(list(A = 1:5, B = 1:5, C = 1:5))
df$value <- runif(nrow(df))
In plyr, I could use a custom function to select this row.
ddply(df, .(A, B), function(x) x[which.max(x$value),])
In dplyr, I am using this code to get the maximum value, but not the rows with maximum value (Column C in this case).
df %>% group_by(A, B) %>%
summarise(max = max(value))
How could I achieve this? Thanks for any suggestion.