I have a huge data frame like this
head(newdata)
V1 V2 V3 V4 V5 V6 V7 V8
1 a 1941 2 14 -73.90 38.60 US009239 4
2 b 1941 2 14 -74.00 36.90 US009239 6
3 c 1941 2 14 -74.00 35.40 US009239 4
5 d 1941 2 15 -74.00 32.60 US009239 7
6 f 1941 2 15 -73.80 31.70 US009239v 1
and what I would like to do is to perform some operation on every subset of data characterised by the same V7. I tried splitting it with
split(data, list(data$V7), drop = TRUE)
and then calculating the min and max of V8 for every element of the list, but it take too much memory and is really slow.
How can I do it?