Thank you Sir. This is really helpful.
I somehow managed to get using subset. But this has resolved part of my query and another struggle is that while I do unique on particular circuitid, I need to pick up the max value in another column (in inboundthroughput) like below... Hope you get this....
I'm trying to obtain using this but its not giving me expected output.
df_INT <- subset(top_INT, circuitid == unique(top_INT$circuitid)) & max(top_INT$inboundthroughput)
Thanks in advance. 