Hi,
I have a matrix with two columns. The first column means "indexes", the second
one contents of those indexes. If I have a MATRIX like this,
> MATRIX
[,1] [,2]
[1,] 1 3
[2,] 5 1
[3,] 2 1
[4,] 1 5
I'd like to get as a result vector the sums of these indexes, something like
this:
> c(8,1,0,0,1)
How to do this?
I did solved it this way, but is there some more elegant way:
RESULTVECTOR=c();
RESULTMATRIX=c();
INDEXES=as.integer(names(table(TRANSP_TABLE[,1])));
for(i in INDEXES)
{
RESULTVECTOR=c(i,sum(MATRIX[,2][MATRIX[,1]==i]))
RESULTMATRIX=rbind(RESULTMATRIX,RESULTVECTOR)
}
row.names(RESULTMATRIX)<-INDEXES;
RESULTMATRIX=RESULTMATRIX[,2];
> RESULTMATRIX
1 2 5
8 1 1
Atte Tenkanen
University of Turku, Finland
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