[R] merge function to combine two tables

[John Kane]

Below , in line

John Kane
Kingston ON Canada


> -----Original Message-----
> From: michael.eisenring at gmx.ch
> Sent: Thu, 14 Mar 2013 11:51:49 +0100
> To: r-help at r-project.org
> Subject: [R] merge function to combine two tables
> 
> Dear R-help members
> 
> I would be grateful if anyone could help me with the following problem:
> 
> I would like to combine two matrices (Schmitt_15 and Schmitt_16, they are
> attached) which have a  species presence/absence x sampling plot
> structure. The aim would be to have in the end only one matrix which
> shows all existing species and their presence/absence on all the
> different plots.
> To do this I used the "merge" function in R.
> The problem is that my matrix in the end shows only 12 species (but there
> are in total about 100!). I don't know why.
> 
> I used the following commands:
> 
> 
> Schmitt_15
> Schmitt_16
> output<-merge(Schmitt_15,Schmitt_16,by="species")

#  you seem to be only picking out the common species in the two  data.frames

ncol(output)
  length(unique(output$species))
  Schmitt_15$species  %in% Schmitt_16$species
  
# This may do what you want. It means that you are taking every speices name found in either file. Is that what you want"
  
newdat  <-  merge(Schmitt_15,Schmitt_16, by="species", all = TRUE)



This gives me a merged file with 

# You seem to have missed a step here since there is no ab object in your code.
> write.table(ab,file="output.txt",sep=",")
> 
> Can anyone help me?
> Thank you very much!
> Michael
> 
> 
> 
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