[R] Multiple subsets of data

[John Kane]

You're definitely doing something I don't understand.
Here's a quick mock-up of the sample data sets you provided.  How do you know if species a in trait is from NA1102 or  AT1302  in com?  I may be blind but I just don't see what you're matching when you use which.  Perhaps you might want to post the which command you're using?

By the way dput is a valuable way of providing sample data. 

trait <- structure(list(Species = c("a", "b", "c"), v1 = c("t", "f", "r"
), v2 = c("y", "j", "y"), v3 = c("h", "u", "u")), .Names = c("Species",
"v1", "v2", "v3"), class = "data.frame", row.names = c(NA, -3L
))

com <- structure(list(community = c("NA1102", "NA1102", "NA0402", "NA0402",
"AT1302", "AT1302"), species = c("a", "c", "b", "c", "a", "b"
)), .Names = c("community", "species"), class = "data.frame", row.names = c(NA,
-6L))






> From: Chris Mcowen <chrismcowen at gmail.com>
> Subject: Re: [R] Multiple subsets of data
> To: "John Kane" <jrkrideau at yahoo.ca>
> Cc: r-help at r-project.org
> Received: Thursday, January 6, 2011, 10:19 AM
> Hi,
> 
> Sorry the formatting has messed up, the common variable is
> species ( spelt different in both but i have corrected this
> now)
> 
> I am having some luck with the which function but am
> struggling to automate it for all communities
> On 6 Jan 2011, at 15:09, John Kane wrote:
> 
> Is there any common variable?  From your description,
> I don't see how you would link a species to a
> community.  I mean if you select species a in df1 how
> would you know what community it is in?
> 
> --- On Thu, 1/6/11, Chris Mcowen <chrismcowen at gmail.com>
> wrote:
> 
> > From: Chris Mcowen <chrismcowen at gmail.com>
> > Subject: [R] Multiple subsets of data
> > To: r-help at r-project.org
> > Received: Thursday, January 6, 2011, 6:29 AM
> > 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.
> > 
> > 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.
> > ______________________________________________
> > R-help at 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.
> > 
> 
> 
> 
>