I want to perform linear regression on groups of consecutive rows--say 5 to 10 such--of two matrices. There are many such potential groups because the matrices have thousands of rows. The matrices are both of the form:
> shp[1:5,16:20] SL495B SL004C SL005C SL005A SL017A -2649 1.06 0.56 NA NA NA -2648 0.97 0.57 NA NA NA -2647 0.46 0.30 NA NA NA -2646 0.92 0.48 NA NA NA -2645 0.82 0.48 NA NA NA That is, they both have NA values, and non-NA values, in the same matrix positions. In my attempts so far, I have had two problems. First, in using the split function (which I assume is essential here), I am unable to split the matrices by groups of rows (say rows 1 to 5, 6 to 10, etc): > shp_split = split(shp,row(shp)) will split the matrix by rows but not by groups thereof. Stumped. Second, I cannot seem to get rid of the NA values, which would prevent the regression even is I could figure out how to split the matrices correctly, e.g.: > shp_split = split(shp,row(shp)) > shp_split = shp_split[!is.na(shp_split)] > shp_split[1] $`1` [1] 0.68 0.28 0.43 0.47 0.64 0.40 0.69 0.56 0.62 0.40 1.01 0.67 0.17 1.36 1.84 1.06 0.56 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA etc IF I solve these problems, will I in fact be able to perform individual linear regressions on the (numerous) collections of 5 to 10 rows? Thanks as always for any insight. Jim Bouldin Research Ecologist Department of Plant Sciences, UC Davis Davis CA, 95616 530-554-1740 ______________________________________________ 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.