I have a dataset. Initially, it has 25 levels for a certain factor, Description.
However, I then subset it, because I am only interested in 2 of the 25 factors. When I subset it, I get the following. The vector lists only the two factors, yet there remain 25 levels: > Quadrats.df$Description [1] Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 [10] Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Emergent 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 [19] Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 [28] Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 Hydroseed 25x75 25 Levels: Black Cottonwood Black Cottonwood Enhanced Emergent Emergent 25x75 Floodplain 1 Floodplain 2 Floodplain 3 Hydroseed 25x75 ... Western Red Cedar Enhanced This seems rather innocuous; however, when I run a by statement, it returns a list with 25 entries, 23 of which are of course NA....is there a way to avoid this? -- View this message in context: http://www.nabble.com/vectors-levels-are-carried-through-to-subsets...-tp25667735p25667735.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
