write.table writes unwanted leading empty column to header when has rownames
export-to-csv, r, write.table
Solution
Citing `?write.table`, section CSV files:
By default there is no column name for a column of row names. If `col.names = NA` and `row.names = TRUE` a blank column name is added, which is the convention used for CSV files to be read by spreadsheets.
So you must do
write.table(a, 'a.txt', col.names=NA)
and you get
"" "A" "B" "C"
"A" 1 4 7
"B" 2 5 8
"C" 3 6 9
Problem
check this example: ``` > a = matrix(1:9, nrow = 3, ncol = 3, dimnames = list(LETTERS[1:3], LETTERS[1:3])) > a A B C A 1 4 7 B 2 5 8 C 3 6 9 ``` the table displays correctly. There are two different ways of writing it to file... `write.csv(a, 'a.csv')` which gives as expected: ``` "","A","B","C" "A",1,4,7 "B",2,5,8 "C",3,6,9 ``` and `write.table(a, 'a.txt')` which screws up ``` "A" "B" "C" "A" 1 4 7 "B" 2 5 8 "C" 3 6 9 ``` indeed, an empty tab is missing.... which is a pain in the butt for downstream things. Is this a bug or a feature? Is there a workaround? (other than `write.table(cbind(rownames(a), a), 'a.txt', row.names=FALSE`) Cheers, yannick