[R] Split column of concatenated data

[Street N.R.]

Hi

I have a column of concatenated information stored in an RG object in the limma package and I need to split this information and then paste the first two pieces of data in each case back into two columns of the RG object.

This is how I am currently doing this


gene.info.split<-strsplit(RG$genes$Name,",",fixed=TRUE)

for (h in 1: length(gene.info.split)){
RG$genes$ID[h]<-gene.info.split[h][[1]][1]
RG$genes$Name[h]<-gene.info.split[h][[1]][2]
}


However, this is very slow and presumably 'messy'. The problem is that there are an inconsistent number of comma separated entries in the original Name column so I cannot do

gene.info.split<-as.data.frame(strsplit(RG$genes$Name,",",fixed=TRUE))

because I get the error message 

Error in data.frame(c("OligoCy3", "SP Control poplar 48pin", "A24", "no length information" : 
        arguments imply differing number of rows: 4, 6, 5, 1

I also can't figure out how to usefully put the [list] data into a matrix (my ignorance I am sure).

Ideally I would be able to put each comma separated item into a column and then simply paste the first and second columns over the RG$genes$Name and RG$genes$ID columns respectively (and do away with the for loop).

Some cases in the original RG$genes$Name has only one piece of information (ie no commas) so I would need a way to fill any blanks with an NA value

If anyone can help me, it would be much appreciated

Nat Street



---
Nathaniel Street
         University of Southampton
         Plants and Environment Lab
      School of Biological Sciences
   Basset Crescent East
   Southampton
 SO16 7PX
       tel: +44 (0) 2380 594268
  fax: +44 (0) 2380 594269
 n.r.street at soton.ac.uk

    http://www.populus.biol.soton.ac.uk/~nat 
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