Hi there, I've got this matrix D with, say 10 rows and 20 columns. For each row I want to sum the first 3 non zero elements and put them in a vector z.
So if the first row D[1,] is 0 3 5 0 8 9 3 2 4 0 then I want z z<-D[1,2]+D[1,3]+D[1,5] But if there are less than 3 non zero elements, those should be summed. If there are no non zero elements, the result must be zero. So if the first row D[1,] is 0 0 3 0 1 0 0 0 0 0 then I want z z<-D[1,3]+D[1,5] Hope someone can help me out! -- View this message in context: http://r.789695.n4.nabble.com/Sum-first-3-non-zero-elements-of-row-tp4667563.html Sent from the datatable-help mailing list archive at Nabble.com. _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
