Here is another way: > xx <- data.frame(P = sample(5, 100, TRUE), M = sample(5, 100, TRUE), id = > 1:100) > require(data.table) > xx <- data.table(xx) # convert to data.table > count <- xx[ + , list(count = length(id)) + , by = list(M, P) + ] > str(count) Classes ‘data.table’ and 'data.frame': 24 obs. of 3 variables: $ M : int 1 1 1 1 1 2 2 2 2 2 ... $ P : int 1 2 3 4 5 1 2 3 4 5 ... $ count: int 5 4 3 2 9 3 3 6 3 7 ... > count M P count 1 1 5 1 2 4 1 3 3 1 4 2 1 5 9 2 1 3 2 2 3 2 3 6 2 4 3
On Mon, Jul 4, 2011 at 5:48 AM, UriB <uribl...@gmail.com> wrote: > I have a matrix of claims at year1 that I get simply by > > claims<-read.csv(file="Claims.csv") > qq1<-claims[claims$Year=="Y1",] > > I have MemberID and ProviderID for every claim in qq1 both are integers > > An example for the type of questions that I want to answer is > how many times ProviderID number 345 appears together with MemberID 23 in > the table qq1 > > In order to answer these questions for every possible ProviderId and every > possible MemberID > I would like to have a matrix that has first column as memberID when every > memberID in qq1 appears only once and columns that have number of appearance > of ProviderID==i for every i that has > sum(qq1$ProviderID==i)>0 > > My question is if there is a simple way to do it in R > Thanks in Advance > > Uri > > -- > View this message in context: > http://r.789695.n4.nabble.com/How-to-build-a-matrix-of-number-of-appearance-tp3643248p3643248.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > -- Jim Holtman Data Munger Guru What is the problem that you are trying to solve? ______________________________________________ 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.
