selecting ith rows of a matrix
probably you want to use seq(), e.g., mat <- matrix(1:500, 100, 5) mat[seq(1, nrow(mat), 2), ] mat[seq(1, nrow(mat), 3), ] mat[seq(1, nrow(mat), 4), ] I hope it helps. Best, Dimitris
Umesh Srinivasan wrote:
Hi all, If I have a huge matrix/ dataframe and I want to create a new matrix/ dataframe with every second (or third, or fourth etc.) row of the original matrix, how can I do it? Any help much appreciated. Thanks, Umesh [[alternative HTML version deleted]]
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Dimitris Rizopoulos Assistant Professor Department of Biostatistics Erasmus University Medical Center Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands Tel: +31/(0)10/7043478 Fax: +31/(0)10/7043014