Subsetting a dataframe based on daily maxima

Question

I have an excel csv with a date/time column and a value associated with that date/time. I\'m trying to write a script that will go through this format (see below), and find 1) t

Answer 1

For another alternative, you could use data.table:

dat_table <- data.table(dat)

dat_table [ , list(is_max = V3==max(V3), V2, V3), by= 'V1'][which(is_max),][,is_max :=NULL]

EDIT as per @MattDowle's comment

dat_table[, .SD[which.max(V3)], by=V1]

For an even simpler data.table solution.