R for loop write table row.names= file names?

Question

It looks like there is no row.names=file.names[i] option when I use the write.table function. For example, assuming in the folder I've 3 files named "file_1", "file_2", and "file_3", then in the output csv file, I would like to see the following results:

"","keyword","totalword"  
"file_1",10,4348  
"file_2",1,1635  
"file_3",1,3237 

    for(i in 1:length(file.names)){
      ## calculate number of keywords and total words for each file within a folder
      x <- data.frame(keyword,totalword) 
      write.csv(x, file="results.csv",row.names = TRUE) 
    }

Using the above code, all I can get is the following:

"","keyword","totalword"  
"1",10,4348  
"2",1,1635  
"3",1,3237  

Anyone knows how to specify the row name using the name of each original file (ie, changing "1" "2" "3" to "file_1", "file_2, "file_3"?

Answer 1

You have the names of the files in 'file.names' so just change
x <- data.frame(keyword,totalword) to
x <- data.frame(file.names[i],keyword,totalword)
You may have to get rid of the row.names = TRUE .

Answer 2

With those data :

keyword<-c(10,1,1)
totalword<-c(4348,1635,3237)

Here are a few options :

x<-data.frame(keyword,totalword,row.names=paste0('file_',1:3))
write.csv(x, file="results.csv",row.names = TRUE) 

or

x<-data.frame(keyword,totalword)
rownames(x)<-paste0('file_',1:3)
write.csv(x, file="results.csv",row.names = TRUE) 

or

write.csv(x,file="results.csv",row.names=paste0('file_',1:3))

all of these will return that in the CSV file :

"","keyword","totalword"
"file_1",10,4348
"file_2",1,1635
"file_3",1,3237

I assumed that you have the 3 rows and that you then write a csv. If you want to write one line in the csv then the next one and so on (one line for each iteration) you could do something like :

write.csv(x,file="results.csv",append=TRUE,row.names=paste0('file_',i))