Re-post data format question (apologies)
on 02/07/2009 01:47 PM Drew Garey wrote:
Hello all,
I have a *.csv file that looks like this (actual file is orders of magnitude
larger):
Site taxa no.ind
forest LMA 1
forest LCY 1
forest SCO 1
meadow LMA 2
meadow LCY 1
meadow PNT 3
I am interested in, but have failed to create, code that efficiently
converts it to a site-by-taxa matrix or data frame that looks like this:
LMA LCY SCO PNT
Forest 1 1 1 0
Meadow 2 1 0 3
With no repeating taxa names and zeros where a taxon is not listed for a
site. Any help would be greatly appreciated.
See ?xtabs If your data is in a data frame called 'DF':
DF
Site taxa no.ind 1 forest LMA 1 2 forest LCY 1 3 forest SCO 1 4 meadow LMA 2 5 meadow LCY 1 6 meadow PNT 3
xtabs(no.ind ~ Site + taxa, data = DF)
taxa Site LCY LMA PNT SCO forest 1 1 0 1 meadow 1 2 3 0 HTH, Marc Schwartz