On read.csv and write.csv
Dear Gabriel,
On 2021-07-01 6:29 p.m., Gabriel Becker wrote:
On Thu, Jul 1, 2021 at 1:46 PM Stephen Ellison <S.Ellison at lgcgroup.com> wrote:
Please run the reproducible example provided.
When you do, you will see that write.csv writes an unnecessary empty
header field ("") over the row names column. This makes the number of
header fields equal to the number of columns _including_ row names. That
causes the original row names to be read as data by read.csv, following the
rule that the number of header fields determines whether row names are
present. read.csv accordingly assumes that the former row names are
unnamed data, calls the unnamed row names column "X" (or X.1 etc if X
exists) and then adds new, default, row names _instead of the original row
names written by write.csv_.
That's not helpful.
This depends on if you are reading the csv via R or something else, I would imagine. It not being "valid" CSV at all would likely cause some programs to choke entirely, I expect. I admit that's conjecture though, I don't have data on that one way or another.
On Excel, for example, opening a .csv file without the empty initial field in the first line will cause the column names to be misaligned. As others have pointed out, .csv files are meant as a sort of least-common-denominator of data exchange, and so following the standard is probably a good idea. Best, John John Fox, Professor Emeritus McMaster University Hamilton, Ontario, Canada web: https://socialsciences.mcmaster.ca/jfox/
~G [[alternative HTML version deleted]]
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