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Another newbie question

5 messages · AllenL, Peter Alspach, jim holtman +1 more

Original
AllenL
# 
Problem: 
I have a data frame with 1s and 0s denoting presence/absence of species
(columns) for particular plot measurements (rows). What I want to do is make
a new column whose entries for each row is a list of the column names in
which a species is present (ie. for row one its entry might read:
"sp1","sp2", etc.). I've tried various functions etc. but can't seem to get
the syntax right/ the correct combination of functions.
Thanks in advance!
-Allen
Peter Alspach
# 
Kia ora Allen

I'm not sure what you have tried or what your level of understanding is.
However, if your dataframe is:
sp1 sp2 sp3
1   0   0   1
2   1   0   1
3   1   1   1
4   0   0   0
'data.frame':   4 obs. of  3 variables:
 $ sp1: int  0 1 1 0
 $ sp2: int  0 0 1 0
 $ sp3: int  1 1 1 0

Then looking at the output from:

paste(names(allen)[as.logical(unlist(allen[2,]))], collapse='; ')

may help you. 

Hei kona ra ...

Peter Alspach
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jim holtman
# 
You did not provide any data, so I will take a guess at what it looks like:
A B C D E F G H I J
1  0 1 0 0 0 1 1 0 0 0
2  0 0 0 0 1 1 0 0 1 0
3  1 1 0 0 1 0 0 0 1 1
4  0 1 1 1 0 1 1 0 0 0
5  0 1 1 0 0 0 1 0 0 1
6  1 0 1 1 0 0 0 0 0 1
7  1 1 0 1 0 0 0 0 0 0
8  0 1 0 1 0 0 1 0 0 0
9  0 1 0 0 0 0 1 0 0 0
10 1 0 1 0 1 1 0 1 0 1
A B C D E F G H I J       match
1  0 1 0 0 0 1 1 0 0 0       B,F,G
2  0 0 0 0 1 1 0 0 1 0       E,F,I
3  1 1 0 0 1 0 0 0 1 1   A,B,E,I,J
4  0 1 1 1 0 1 1 0 0 0   B,C,D,F,G
5  0 1 1 0 0 0 1 0 0 1     B,C,G,J
6  1 0 1 1 0 0 0 0 0 1     A,C,D,J
7  1 1 0 1 0 0 0 0 0 0       A,B,D
8  0 1 0 1 0 0 1 0 0 0       B,D,G
9  0 1 0 0 0 0 1 0 0 0         B,G
10 1 0 1 0 1 1 0 1 0 1 A,C,E,F,H,J

        
On Wed, Jan 7, 2009 at 1:28 PM, AllenL <allen.larocque at gmail.com> wrote:

            

      
      
      
    

        

      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Dimitris Rizopoulos
    

    

      
      #
    

  


  

      
try the following:

dat <- data.frame(
     sp1 = rbinom(10, 1, 0.5),
     sp2 = rbinom(10, 1, 0.5),
     sp3 = rbinom(10, 1, 0.5),
     sp4 = rbinom(10, 1, 0.5),
     sp5 = rbinom(10, 1, 0.5),
     sp6 = rbinom(10, 1, 0.5)
)

ind <- sapply(dat, as.logical)
dat$Sp <- apply(ind, 1, function (x, nams)
     paste(nams[x], collapse = "; "), nams = names(dat))
dat


I hope it helps.

Best,
Dimitris

        
AllenL wrote:

            

      
      
      
    

        

  
    

      
      
    

  


  


      

    

    
1 day later

    

      
      

        


  

        

      AllenL
    

    

      
      #
    

  


  

      
Thank you all! In future I will include examples of my code to make things
simpler for you. This is what I settled on:

Sp.presence<-Data[,14:31]   ##The subset of my data set I'm interested in
(the presence/absence data)
Sp.presence$Species<-apply(Sp.presence,1,function(x)
{c(paste(names(Sp.presence)[x==1],collapse=","))})

Yay!
-Allen

        
AllenL wrote: