write.table and append

I believe your problem stems from using ifelse() actually ... it
requires the statements which it runs to return a value with the same
shape as the test, which write.table() isn't doing.

Just change it to a regular if with an else and you'll be fine:

for(i in 1:2){
  mat <- data.frame(sample(1:30,9),3,3)
  colnames(mat) <- letters[1:3]
  if(i == 1){
    write.table(mat,paste('test.txt',sep=''),row.names=F)
  } else {
    write.table(mat,paste('test.txt',sep=''),row.names=F,col.names=F,append=TRUE)
  }
}

Hope that helps,

Louis

Hi,

I am trying to append tables on file with this sample code:

        for(i in 1:2){
            mat <- data.frame(sample(1:30,9),3,3)
            colnames(mat) <- letters[1:3]
            ifelse(i ==
1,write.table(mat,paste('test.txt',sep=''),row.names=F),

write.table(mat,paste('test.txt',sep=''),row.names=F,col.names=F,append=TRUE))
        }

However, this gives an error:

"Error in ifelse(i == 1, write.table(mat, paste("test.txt", sep = ""),  :
  replacement has length zero"

- Should I be passing in some other parameters or using a different
function to append tables to file?

thanks!

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130208/3bee68df/attachment.pl>

Hi,

Hi,

I am trying to append tables on file with this sample code:

       for(i in 1:2){
           mat <- data.frame(sample(1:30,9),3,3)
           colnames(mat) <- letters[1:3]
           ifelse(i ==
1,write.table(mat,paste('test.txt',sep=''),row.names=F),

write.table(mat,paste('test.txt',sep=''),row.names=F,col.names=F,append=TRUE))
       }

However, this gives an error:

"Error in ifelse(i == 1, write.table(mat, paste("test.txt", sep = ""),  :
 replacement has length zero"

- Should I be passing in some other parameters or using a different
function to append tables to file?

You might try assign each parameter based upon the value of i instead of trying to manage two different calls to write.table through an ifelse function.  ifelse doesn't seem to like the value returned by write.table (NULL).  Here's a simply example...

ok <- ifelse( TRUE, NULL, NULL)

Error in ifelse(TRUE, NULL, NULL) : replacement has length zero

ok <- ifelse( FALSE, NULL, NULL)

Error in ifelse(FALSE, NULL, NULL) : replacement has length zero

I think that is what the warning in ?ifelse is alluding to.  You would only know that write.table returns NULL if you have bitten by it before.  I have bite marks.

for(i in 1:2){
   mat <- data.frame(sample(1:30,9),3,3)
   colnames(mat) <- letters[1:3]
   write.table(mat, file = "test.txt", 
      row.names = FALSE,
      col.names = (i == 1),
      append = (i != 1) )       
}


Cheers,
Ben

thanks!

	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Ben Tupper
Bigelow Laboratory for Ocean Sciences
60 Bigelow Drive, P.O. Box 380
East Boothbay, Maine 04544
http://www.bigelow.org

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130208/60c442f5/attachment.pl>