csv module and NULL data byte

[Andrew McNamara]

>> 	Last time I read the documentation, it was recommended that
>> the file be opened in BINARY mode ("rb").
>
>It recommends binary mode, but seems to largely work fine with
>text/ascii mode or even arbitrary iterables.  I've not seen the
>rationale behind the binary recommendation, but in 10+ years of using
>the csv module, I've not found any issues in using text/ascii mode
>that were solved by switching to using binary mode.

The CSV module was originally written by Dave Cole. I subsequently
made changes necessary to get it included a standard part of Python.
I also implemented the "dialect" logic, and I put a lot of time into
making the parser and generator produce the same results as Excel.

That particular recommendation is necessary because Excel has some
particular behaviours around CR and LF and quoting. For the parser to
produce the same result as Excel, it must see the raw bytes with no
re-ordering or suppression of CRs.

Unfortunately, I haven't had time to be involved in the module for a few
years. I wasn't involved with the Unicode changes necessary in Python 3,
and I have not verified that it is still compatible with recent versions
of Excel.

-- 
Andrew McNamara, Senior Developer, Object Craft
http://www.object-craft.com.au/