Dear all,
I have a data set as follows:
ID cycle.number cycle.result
1 2525 1 38
2 2525 2 38
3 2525 3 25
4 2525 4 25
5 2525 5 25
6 2525 6 25
7 2531 1 38
8 2531 2 38
9 2078 1 38
10 2078 2 38
I want to find out the maximum cycle.number for each ID, and later find the
corresponding cycle.result for that cycle.
I have already managed to pull out the maximum cycle by using a for loop:
max.cycle <- vector()
patients <- (levels(factor(ID)))
for (i in 1:length(patients)) {
max.cycle[i] <- max(cycle.number[(ID %in% patients[i] )])
}
But i would like to know if there is a better or more elegant way of pulling
out the maximum cycle.number for each ID? Perhaps without the need for using
a for loop?
Many thanks,
Caroline
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Try this: If cycle.number is ordered: do.call(rbind, lapply(split(x, x$ID), tail, 1)) On Sat, Sep 12, 2009 at 12:36 PM, caroline choong <carolinevchoong@gmail.com> wrote:> Dear all, > I have a data set as follows: > > ID cycle.number cycle.result > 1 2525 1 38 > 2 2525 2 38 > 3 2525 3 25 > 4 2525 4 25 > 5 2525 5 25 > 6 2525 6 25 > 7 2531 1 38 > 8 2531 2 38 > 9 2078 1 38 > 10 2078 2 38 > > I want to find out the maximum cycle.number for each ID, and later find the > corresponding cycle.result for that cycle. > > I have already managed to pull out the maximum cycle by using a for loop: > > max.cycle <- vector() > patients <- (levels(factor(ID))) > for (i in 1:length(patients)) { > > max.cycle[i] <- max(cycle.number[(ID %in% patients[i] )]) > > } > > But i would like to know if there is a better or more elegant way of > pulling > out the maximum cycle.number for each ID? Perhaps without the need for > using > a for loop? > > Many thanks, > Caroline > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[alternative HTML version deleted]]
On Sep 12, 2009, at 11:36 AM, caroline choong wrote:> Dear all, > I have a data set as follows: > > ID cycle.number cycle.result > 1 2525 1 38 > 2 2525 2 38 > 3 2525 3 25 > 4 2525 4 25 > 5 2525 5 25 > 6 2525 6 25 > 7 2531 1 38 > 8 2531 2 38 > 9 2078 1 38 > 10 2078 2 38 > > I want to find out the maximum cycle.number for each ID, and later > find the > corresponding cycle.result for that cycle. > > I have already managed to pull out the maximum cycle by using a for > loop: > > max.cycle <- vector() > patients <- (levels(factor(ID))) > for (i in 1:length(patients)) { > > max.cycle[i] <- max(cycle.number[(ID %in% patients[i] )]) > > } > > But i would like to know if there is a better or more elegant way of > pulling > out the maximum cycle.number for each ID?There is: ?tapply > patients <- read.table(textConnection(" ID cycle.number cycle.result + 1 2525 1 38 + 2 2525 2 38 + 3 2525 3 25 + 4 2525 4 25 + 5 2525 5 25 + 6 2525 6 25 + 7 2531 1 38 + 8 2531 2 38 + 9 2078 1 38 + 10 2078 2 38"), header=TRUE) > tapply(patients$cycle.number, patients$ID, max) 2078 2525 2531 2 6 2> Perhaps without the need for using > a for loop? > > Many thanks,David Winsemius, MD Heritage Laboratories West Hartford, CT
Many thanks, truly a simple and elegant solution! Caroline On Sun, Sep 13, 2009 at 12:08 AM, David Winsemius <dwinsemius at comcast.net> wrote:> > On Sep 12, 2009, at 11:36 AM, caroline choong wrote: > >> Dear all, >> I have a data set as follows: >> >> ? ? ? ?ID ? ? ? ? ? ? ? cycle.number ? ? ?cycle.result >> 1 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 >> 2 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38 >> 3 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?3 ? ? ? ? ? ? ? ? ? 25 >> 4 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?4 ? ? ? ? ? ? ? ? ? 25 >> 5 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?5 ? ? ? ? ? ? ? ? ? 25 >> 6 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?6 ? ? ? ? ? ? ? ? ? 25 >> 7 ? ? 2531 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 >> 8 ? ? 2531 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38 >> 9 ? ? 2078 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 >> 10 ? ?2078 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38 >> >> I want to find out the maximum cycle.number for each ID, and later find the >> corresponding cycle.result for that cycle. >> >> I have already managed to pull out the maximum cycle by using a for loop: >> >> max.cycle <- vector() >> patients <- (levels(factor(ID))) >> for (i in 1:length(patients)) { >> >> max.cycle[i] <- max(cycle.number[(ID %in% patients[i] )]) >> >> } >> >> But i would like to know if there is a better or more elegant way of pulling >> out the maximum cycle.number for each ID? > > There is: > > ?tapply > > > patients <- read.table(textConnection(" ? ? ? ?ID ? ? ? ? ? ? ? cycle.number ? ? ?cycle.result > + 1 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 > + 2 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38 > + 3 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?3 ? ? ? ? ? ? ? ? ? 25 > + 4 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?4 ? ? ? ? ? ? ? ? ? 25 > + 5 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?5 ? ? ? ? ? ? ? ? ? 25 > + 6 ? ? 2525 ? ? ? ? ? ? ? ? ? ? ?6 ? ? ? ? ? ? ? ? ? 25 > + 7 ? ? 2531 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 > + 8 ? ? 2531 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38 > + 9 ? ? 2078 ? ? ? ? ? ? ? ? ? ? ?1 ? ? ? ? ? ? ? ? ? 38 > + 10 ? ?2078 ? ? ? ? ? ? ? ? ? ? ?2 ? ? ? ? ? ? ? ? ? 38"), header=TRUE) > > > tapply(patients$cycle.number, patients$ID, max) > 2078 2525 2531 > ? 2 ? ?6 ? ?2 > > >> Perhaps without the need for using >> a for loop? >> >> Many thanks, > > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT >