Thanks, I think it was the odd variable that was named "f.env$zone" I removed
that column and suddenly things started working
--
Kendra Maas Mitchell, Ph.D.
Post Doctoral Research Fellow
University of British Columbia
604-822-5646
________________________________
From: Dixon, Philip M [STAT] [pdi...@iastate.edu]
Sent: Thursday, December 05, 2013 8:42 AM
To: Mitchell, Kendra
Cc: r-sig-ecology@r-project.org
Subject: NA error in envfit
Kendra,
I wonder if the problem is a factor level with no observations. One of the
frustrating things about factors (class variables) in R is that the list of
levels is stored separately from the data. This can cause all sorts of
problems if you create the factor, then subset the data, and the subset is
missing one or more levels of the factor. You are subsetting your data, so
this may be the source of the problem.
My working philosophy is to keep variables as character strings or numbers
until just before I need the factors. That avoids any issues with extraneous
levels. That means reading data sets (.txt or .csv files) with as.is=TRUE to
avoid default creation of factors. relevel() may recreate the list of levels.
I usually use factor(as.character(variable)) to flip a factor to a vector of
character strings then back to a factor with the correct set of levels.
Best wishes,
Philip Dixon
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