Is this what you want: > yrData <- data.frame(year=sample(1990:2000, 100, TRUE), + species=sample(1:3,100,TRUE), loc=sample(1:2,100,TRUE)) > byYear <- split(yrData, yrData$year) > > byYear[1:3] $`1990` year species loc 39 1990 3 2 57 1990 3 1 62 1990 1 1 68 1990 2 1 71 1990 2 2 80 1990 3 2 85 1990 3 2 90 1990 3 2 93 1990 2 1 $`1991` year species loc 9 1991 2 2 19 1991 3 2 21 1991 1 2 22 1991 3 1 25 1991 2 2 30 1991 1 1 54 1991 1 1 65 1991 1 1 79 1991 2 2 84 1991 3 1 91 1991 2 1 98 1991 2 1 $`1992` year species loc 4 1992 2 1 5 1992 1 2 15 1992 2 2 16 1992 2 1 32 1992 3 2 75 1992 1 2 95 1992 3 1
On Wed, Mar 10, 2010 at 12:07 PM, Lanna Jin <lanna...@gmail.com> wrote: > Hi All, > > If given a dataframe (long form) with Year, Species, and Location, > How would I write a function that would create a unique matrix of Species & > Location for each Year? > > What I've tried doing is the following: > > data #dataframe > dataT<-table(data$Species,data$Location,data$Year) #creates tables of > Species vs Location for each Year > > But I'm encountering issues individually indexing the tables and converting > them into matrices in one fell swoop. > > r1997<-as.matrix(tableT[,,"1997"]) #How I would do it individually; but I > can I make matrices for each year as a function? > > Thanks in advance for your suggestions! > > -- > Lanna Jin > > lanna...@gmail.com > 510-898-8525 > > [[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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? [[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.
