[R] Finding all rows of a matrix equal to vector

[Sebastian Lerch]

Hi everyone,

my question might be very trivial, but I could not come up with an answer...

I want to find out how often a matrix contains a certain vector as row:

x1<-c(1,2,3)
x2<-c(1,5,6)
x3<-c(7,8,9)
A<-matrix(c(rep(x1,5),rep(x2,5),rep(x3,5),rep(x1,5)),nrow=20,ncol=3,byrow=T)

How can I find out, how many times x1 is a row of A?

Thanks in advance and best regards,
Sebastian