[R] write.csv: set the name of the column containing the row.names

[Luca Cerone]

Hi everybody,
I am sorry if this is a silly question (I have tried to search it at
http://tolstoy.newcastle.edu.au/R/ but I get a 404 page).

I have a script writing some data.frames to csv files.
I write the csv files using the write.csv function and the option
row.names=TRUE.
Everything works fine, except that I am not able to set the name of
the column holding the row.names.

For example I tried to set the column name to ID like this:

    df = data.frame(a=c(1,2,3), b=c(3,4,5))
    rownames(df) = c("A","B","C")

    write.csv(df, row.names=TRUE, colnames=c("ID", colnames(df)))

This fails with the following error:
    Error in write.table(df, row.names = TRUE, colnames = c("ID",
colnames(df)),  :
          unused argument (colnames = c("ID", colnames(df)))

How can I do this? I have tried to use write.table() as well, but it
seems I never get to set the options right.

Thanks a lot in advance for the help,

Cheers,
Luca