Hello List, I have a database which consist of 912 plots. For each plot, I have the presence/absence information of 260 species of plants and also 5 different environmental variables (ddeg, mind, srad, slp, topo).
The dataframe looks like this: Plot_Number X Y ddeg mind srad slp topo Galium_mollugo Gentiana_nivalis 1 1 557747.6 149726.8 2598 -625 236363 8 176 0 0 2 2 572499.4 145503.5 2178 -176 161970 14 -137 0 0 3 3 579100.4 151800.4 1208 632 267572 33 129 0 0 4 4 581301.7 150300.1 1645 83 246633 15 -70 0 0 5 5 579838.7 124770.9 1102 1637 158300 2 -231 0 0 6 6 577011.1 121328.6 731 2223 180286 41 70 0 0 Now, what I wanted to do is to calculate spatial autocorrelation of each environmental variable for each species, but only for the plots where the species is present. I will use the correlog function of the package ncf (doesn’t really matter). The correlog function work with an argument X which is the longitude, an argument Y which is the latitude and an argument Z which is the variable you want to test for autocorrelation (in my case, the different environmental variables). So, for the first species I have the following script: ddeg.correlog.9<-correlog(plant[plant[,9]=="1", 2], plant[plant[,9]=="1", 3], plant[plant[,9]=="1", 4]) X = plant[plant[,9]=="1", 2] —> only the X coordinate where my species 9 is present Y = plant[plant[,9]=="1", 3] —> only the Y coordinate where my species 9 is present Z = plant[plant[,9]=="1", 4] —> only the value of the environmental variable where my species 9 is present plant: dataframe 9: column corresponding to the first species 2: column corresponding to the X coordinate 3: column correspondind to the Y coordinate 4: column corresponding to the first environmental variable So my question is: how do I repeat this script for every species (basically, I just have to change the number « 9 » into 10, 11 and so on) ? I try to write a function but I’m new in R and didn’t manage to do it. I was also considering to use the function « lapply », but I don’t think I can use it in this case, isn’t it? Thank you very much for your help ! Sarah ______________________________________________ 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.
