[R] function to create multiple matrices

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

Re: [R] function to create multiple matrices

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