I'm trying to select a subset of a dataframe while dropping some factors. While the dataset gets smaller all Factor levels remain and I need to get rid of them. Strangely enough, I am almost certain that the same code on the same data worked OK earlier today - and it is not the first time that I'm not able to replicate earlier results with this command (I know, I might just be going crazy). What am I doing wrong?
I'm working on Windows Server 2003, R 2.1.0 (2005-04-18). > str(spray) `data.frame': 370 obs. of 7 variables: $ PD : Factor w/ 8 levels "Botrytis","Downy",..: 2 2 2 2 4 2 2 5 5 5 ... $ postSpmtsQ: num 1309 1309 384 384 1044 ... $ ante62Q : num 284 284 218 218 366 ... $ ante08Q : num 331 331 228 228 492 ... $ ante29Q : num 297 297 1067 1067 1034 ... $ ante16Q : num 0 0 0.2 0.2 0 0 0 6.7 0 31.5 ... $ Trt : Factor w/ 41 levels "Acrobat MZ WP",..: 27 5 27 5 36 27 5 24 24 24 ... > sprayS <- spray[spray$PD == "Spidermites", , drop = TRUE] > str(sprayS) `data.frame': 111 obs. of 7 variables: $ PD : Factor w/ 8 levels "Botrytis","Downy",..: 5 5 5 5 5 5 5 5 5 5 ... $ postSpmtsQ: num 13395 31588 84254 136 619 ... $ ante62Q : num 1357 21187 21819 218 237 ... $ ante08Q : num 973 21740 25112 228 134 ... $ ante29Q : num 2103 106970 66676 1067 119 ... $ ante16Q : num 6.7 0 31.5 0.2 0 0 0 0 14.3 0 ... $ Trt : Factor w/ 41 levels "Acrobat MZ WP",..: 24 24 24 24 24 24 24 24 24 24 ... > table(sprayS$Trt) Acrobat MZ WP Agrifos Apollo 50 SC CALMAG 0 0 13 0 DM-31 Dynamec 1.8 EC Equation Pro DF Evisect S 0 13 0 0 Flint Floramite Impulse Karate 0 15 0 0 Karate zeon Melody Meltatox 40 EC MKP 0 0 0 0 Molasses Nembicidine Nimrod 250 EC Nissorun 10 EC 0 0 0 12 Oberon Orthene 75 WP Oscar 20 SC Pegasus 15 0 9 26 Polar 50 WSG Potfos Proplant Pyrus 0 0 0 0 Ridomil MZ 63 5WP Rovral aqua flo Score 250 EC Secure 36 SC 0 0 0 8 Sequestrone Shavit f Sporekill Stroby 50 WG 0 0 0 0 Switch Tracer Trafos K Vandozeb 0 0 0 0 Vitomex 0 cheers, Mikkel ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html