Try this: split(mapply(function(x, y)pres.test(x, y), DF$pop1995, DF$pop2000), DF$country)
On Wed, Oct 29, 2008 at 10:19 AM, Corey Sparks <[EMAIL PROTECTED]>wrote: > Dear list, > I have the function (as a simple example, which is actually part of a > larger function) > > pres.test<-function(N0=N0, N1=N1) > { > dt<-5 > r<-log(N1/N0)/dt > r > } > > which calculates the annual growth rates in a population > > Where N0 is the population classified into age intervals, say 5 years, at > time=1995, and N1 is the population by 5 year age classes at time=2000. > > For example some data like this are: > country pop1995 pop2000 > 1 1712 1940 > 1 1329 1535 > 1 1101 1268 > 1 911 1048 > 1 758 859 > 2 627 710 > 2 513 584 > 2 420 475 > 2 754 965 > 2 638 741 > > I want to use the tapply function to apply the pres.test function over all > countries in my data table (the real data have ~150 countries and 10 age > classes), but I can't seem to get tapply to take as input to FUN more than > one variable, for example I tried: > > popdat<-cbind(dat2.sub$pop1995, dat2.sub$pop2000) #try to force the two > time points into a vector form > > tapply(popdat, dat2.sub$country, pres.test, ...=list(N0=popdat[,1], > N1=popdat[,2])) #tried to pass the other arguments that pres.test needs via > ... > > And got the error: > Error in tapply(popdat, dat2.sub$Country, pres.test, ... = list(N0 = > popdat[, : > arguments must have same length > > I see that the function mapply will take multiple arguements, but I don't > think it will use an INDEX like tapply. > > Any comments or clarification would be most appreciated. > > Corey > > -- > Corey Sparks > Assistant Professor > Department of Demography and Organization Studies > University of Texas at San Antonio > One UTSA Circle > San Antonio, TX 78249 > 210-458-6858 > [EMAIL PROTECTED] > https://rowdyspace.utsa.edu/users/ozd504/www/index.htm > > ______________________________________________ > 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]]
______________________________________________ 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.