On Tue, 18 Nov 2003, Jeff D. Hamann wrote:
> Can someone tell me why this is since I can't seem to find an explination in > the docs or FAQ for this. > > Since there are no "BM" in the mtrs data.frame, but only in the "parent" > data.frame (trees), I'm assuming the subset data.frame is still associated > with the original. Is that correct and how would I create a completly > separate data.frame since I'll be using by, lapply and such on the subset > data.frame using "sp" which currently causes by to choke... > > > mtrs <- trees[trees$m == 1,] > > mtrs > plot tree sp m dbh tht bfvol cfvol > 1 1 1 DF 1 44 185 3825.79 622.97 > 2 1 2 DF 1 38 188 3166.69 504.12 > 26 3 1 DF 1 42 185 3568.80 578.09 > 51 5 4 DF 1 30 189 2071.36 348.28 > 67 7 1 DF 1 33 168 2036.30 342.90 > 70 7 4 DF 1 45 180 3665.82 621.90 > 71 7 5 DF 1 30 160 1530.88 274.69 > 81 9 1 DF 1 44 175 3398.52 576.79 > 82 9 2 DF 1 68 205 9516.82 1461.21 > 95 11 1 DF 1 30 170 1775.60 299.54 > 96 11 2 DF 1 44 197 4249.98 680.64 > 97 11 3 DF 1 44 187 3914.88 632.42 > 107 11 13 WH 1 44 175 3398.52 576.79 > 121 13 2 WF 1 48 205 5241.14 827.57 > 126 13 7 DF 1 40 182 3188.77 522.43 > 138 15 2 DF 1 69 182 7852.22 1285.42 > 143 15 7 DF 1 28 142 1146.77 207.67 > 159 17 9 DF 1 12 88 99.13 25.43 > 177 19 7 DF 1 37 162 2309.06 391.48 > > attributes( mtrs$sp ) > $class > [1] "factor" > > $levels > [1] "BM" "DF" "WF" "WH" > A factor remembers all its levels unless you tell to drop them as in: mtrs <- trees[trees$m == 1, , drop = TRUE] Uwe Ligges ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
