[R] Exporting columns into multiple files - loop query

[WOOD, Matthew]

Hi,

I'm using a loop to extract 2 columns from an array into multiple files. 
I can use the following to export 3 files, containing column 'ID' with one of
the three event columns.

> ID<-c("A","B","C","D","E","F")
> event1<-c(0,1,0,0,1,0)
> event2<-c(1,1,0,1,0,0)
> event3<-c(1,0,1,0,1,0)
> data<-cbind(ID,event1,event2,event3)
> data
     ID  event1 event2 event3
[1,] "A" "0"    "1"    "1"   
[2,] "B" "1"    "1"    "0"   
[3,] "C" "0"    "0"    "1"   
[4,] "D" "0"    "1"    "0"   
[5,] "E" "1"    "0"    "1"   
[6,] "F" "0"    "0"    "0"   

The data represent individuals that are either seen (1) or not seen (0) on
several occasions.
> 
> n<-ncol(data)
> 
> for(i in 2:n) {
+ df<-data.frame(data[,i],ID) 
+ myfile<-gsub("( )", "",paste(i,".txt")) # name file by year 
+ write.table(df, file=myfile,
sep="\t",row.names=F,col.names=F,quote=FALSE,append=FALSE) 
+ }  

My question: How can I add a function to this loop, to delete rows in the
data frame in which the event is equal to zero? 

An desired file output would be:
     ID  event2
[1,] "A" "1"      
[2,] "B" "1"      
[3,] "D" "1"   

I can handle this taking each file separately using subscripts, but my
attempts to amend the loop, and be able to run this code on a bunch of large
mutliple event files, have failed.

With grateful thanks in advance,

Matt

--
Matt Wood
Department of Natural and Social Sciences
University of Gloucestershire
Francis Close Hall
Cheltenham 
GL50 4AZ



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