A = matrix(1:10,nrow=5)
B = A[-c(1,2,3),];
So
> A
[,1] [,2]
[1,] 1 6
[2,] 2 7
[3,] 3 8
[4,] 4 9
[5,] 5 10
and
> B
[,1] [,2]
[1,] 4 9
[2,] 5 10
I would like to compare A and B in order to find in which rows of A I can
find the rows of B. Something similar to %in% with one dimensional arrays.
In the example above, the answer should be 4 and 5.
I did a function to do it (see it below), it gives me the correct answer
for this toy example, but the excess of for-loops makes it extremely slow
for larger matrices. I was wondering if there is a better way to do this
kind of comparison. Any idea? Sorry if it is a stupid question.
matbinmata<-function(B,A){
res<-c();
rowsB = length(B[,1]);
rowsA = length(A[,1]);
colsB = length(B[1,]);
colsA = length(A[1,]);
for (i in 1:rowsB){
for (j in 1:colsB){
for (k in 1:rowsA){
for (l in 1:colsA){
if(A[k,l]==B[i,j]){res<-c(res,k);}
}
}
}
}
return(unique(sort(res)));
}
Best,
Charles
--
Um axé! :)
--
Charles Novaes de Santana, PhD
http://www.imedea.uib-csic.es/~charles
[[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.
