write.table writes unwanted leading empty column to header when has rownames

Question

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

Answer 1

For anyone working in the tidyverse (dplyr, etc.), the rownames_to_column() function from the tibble package can be used to easily convert row.names to a column, e.g.:

library('tibble')
a = as.data.frame(matrix(1:9, nrow=3, ncol=3, 
                  dimnames=list(LETTERS[1:3], LETTERS[1:3])))

a %>% rownames_to_column('my_id')

  my_id A B C
1     A 1 4 7
2     B 2 5 8
3     C 3 6 9

Combining this with the row.names=FALSE option in write.table() results in output with header names for all columns.