[issue7198] Extraneous newlines with csv.writer on Windows

[John Machin]

John Machin <sjmachin at users.sourceforge.net> added the comment:

Skip, I'm WRITING, not reading.. Please read the 3.1 documentation for csv.writer. It does NOT mention newline='', and neither does the example. Please fix.

Other problems with the examples: (1) They encourage a bad habit (open inside the call to reader/writer); good practice is to retain the reference to the file handle (preferably with a "with" statement) so that it can be closed properly. (2) delimiter=' ' is very unrealistic.

The documentation for both 2.x and 3.x should be much more explicit about what is needed in open() for csv to work properly and portably:

2.x read: use mode='rb' -- otherwise fail on Windows
2.x write: use mode='wb' -- otherwise fail on Windows
3.x read: use newline='' -- otherwise fail unconditionally(?)
3.x write: use newline='' -- otherwise fail on Windows

The 2.7 documentation says """If csvfile is a file object, it must be opened with the 'b' flag on platforms where that makes a difference""" ... in my experience, people are left asking "what platforms? what difference?"; Windows should be mentioned explicitly.

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versions: +Python 2.7, Python 3.2, Python 3.3

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<http://bugs.python.org/issue7198>
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