On Jan 6, 2011, at 6:36 AM, Chris Mcowen wrote:
Dear List,
I have a data frame called trait with roughly 800 species in, each
species have 15 columns of information:
Species 1 2 3 etc..
a t y h
b f j u
c r y u
etc..
I then have another data frame called com with the composition of
species in each region, there are 506 different communities:
community species
NA1102 a
NA1102 c
NA0402 b
NA0402 c
AT1302 a
AT1302 b
etc..
What i want to do is extract the information held in the first data
frame for each community and save this as a new data frame.
> tapply(comm.info$species, comm.info$community, c)
$AT1302
[1] 1 2
$NA0402
[1] 2 3
$NA1102
[1] 1 3
> lapply( tapply(comm.info$species, comm.info$community, c),
function(x){ sp.info[x, ]} )
$AT1302
Species X1 X2 X3
1 a t y h
2 b f j u
$NA0402
Species X1 X2 X3
2 b f j u
3 c r y u
$NA1102
Species X1 X2 X3
1 a t y h
3 c r y u
Might have looked more compact if I had assigned the output of tapply
to an intermediate list:
comm.sp <- tapply(comm.info$species, comm.info$community, c)
lapply( comm.sp , function(x){ sp.info[x, ]} )
Resulting in : -
community_NA1102
a t y h
c r y u
community_NA0402
b f j u
c r y u
Thanks in advance for any suggestions / code.
David Winsemius, MD
West Hartford, CT
______________________________________________
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.
