Hi, On Feb 8, 2013, at 9:40 AM, Brian Smith wrote:
> 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@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 ______________________________________________ R-help@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.