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Multiple subsets of data

4 messages · John Kane, Chris Mcowen

Chris Mcowen
# 
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.
John Kane
# 
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:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Chris Mcowen
    

    

      
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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:

        

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      John Kane
    

    

      
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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))