Hello. Does anyone know of an existing function that takes a list in the form of:
Plot1 Species1 Abundance1 Plot1 Species2 Abundance2 Plot2 Species1 Abundance1 Plot2 Species3 Abundance3 . . . PlotN SpeciesN AbundanceN and translates into a matrix in the form of Species1 Species2.... SpeciesN Plot1 Abundance1 Abundance2... AbundanceN Plot2 Abundance1 Abundance2... AbundanceN . . . PlotN AbundanceN AbundanceN... AbundanceN This is a basic operation used in the initial stages of ordination etc of ecological data (vegetation or other species) that is usually stored in a database or flatfile in the list format above. It is similar to a cross tabulation like the function xtabs(), however its useful to be able to control whether a measured abundance for a taxa is included or a boolean (presence/absence) for the taxa in a given plot. Im new to such analyses in R, but before writing it myself hope or suspect that such a function or library is out there (although I dont see it after some quick searching in things like Vegan or BiodivesityR or labdsv). Thanks billy ______________________________________________ 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.