How about something like this? jonas <- data.frame(time = seq(100, 216000, by = 150), crobs = rnorm(1440)) head(jonas)
jonas$halfhour <- cut(jonas$time, breaks = seq(from = 0, to = 216000, by = 1800)) head(jonas) tapply(jonas$crobs, INDEX = list(jonas$halfhour), FUN = mean) # or aggregate(crobs ~ halfhour, data = jonas, FUN = mean) #or by(data = jonas, INDICES = jonas$halfhour, FUN = function(x) mean(x$crobs)) Cheers, Roman On Mon, Apr 22, 2013 at 12:13 PM, Jonas Steenholdt Sørensen < jonas.steenho...@gmail.com> wrote: > > Hi everbody > > > > I'm working on my bachelor thesis on clearance rate for mussel and need > some help R. First have a look at the DF > > > > Time CRobs > > 150 4.6589 > > 300 3.9685 > > 450 4.0124 > > ...... ........... > > 216000 1.0281 > > > > These data is just made up, but is give some idea of the DF. I want to > simplify my data and instead of having 144 rows of clearance rate, I want > to look at the average within haft an hour. Like this: > > > > Time avgCRobs > > 1800 =average from 150-1800 > > 3600 =average from 1800-3600 > > ..... > > 21600 =average from 19800-21600 > > > > I have talk to one of my friend, that working mainly on C++ and he try > with a loop function without any help and other of my college and friends > from my studies couldn't help either. So I'm hoping there is one that could > lead my on the right direction. > > _______________________________________________ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > -- In God we trust, all others bring data. [[alternative HTML version deleted]]
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