search for: elevcat

...pecting R to have something analogous to the =count function in Excel, but I can't find anything. I simply want to count the data for a given category. I've been using the ddply() function in the plyr package to summarize means and st dev of my data, with this code: ddply(NZ_Conifers,.(ElevCat, DataSource, SizeClass), summarise, avgDensity=mean(Density), sdDensity=sd(Density), n=sum(Density)) and that gives me results that look like this: ElevCat DataSource SizeClass avgDensity sdDensity n 1 Elev1 FIA Class1 38.67768 46.6673478 734.87598 2 Elev1...

I'm having a hard time figuring out how to group results by certain factors in R. I have data with the following headings: [1] "Time" "Plot" "LatCat" "Elevation" "ElevCat" "Aspect" "AspCat" "Slope" [9] "SlopeCat" "Species" "SizeClass" "Stems" and I'm trying to use a GLM to test differences in "Stems" for different categories/factors - most importantly, I want to gr...

...ng a new class, that would be preferable. I've also attached a more detailed sample of data. Thanks, Chris Dolanc -- Christopher R. Dolanc Post-doctoral Researcher University of Montana and UC-Davis -------------- next part -------------- Data Plot Lat LatCat Elevation ElevCat Type SizeClass Stems Area Density 5171 VTM 39C16 39.76282 Lat6 1500 Elev1 Conifer Class3 0 751.5347 0.00000 5172 VTM 39C16 39.76282 Lat6 1500 Elev1 Conifer Class4 1 751.5347 13.30611 5771 VTM 39F11 39.57721 Lat6 50...

I have data that looks like this: > df1 group id 1 red A 2 red B 3 red C 4 blue D 5 blue E 6 blue F I want a list of the groups containing vectors with the ids. I am avoiding subset(), as it is only recommended for interactive use. Here's what I have so far: df1 <- data.frame(group=c("red", "red", "red", "blue",