*csvfile* can be any object which supports the :term:`iterator` protocol and returns a
string each time its :meth:`!__next__` method is called --- :term:`file objects
<file object>` and list objects are both suitable. If *csvfile* is a file object,
- it should be opened with ``newline=''``. [#]_ An optional
+ it should be opened with ``newline=''``. [1]_ An optional
*dialect* parameter can be given which is used to define a set of parameters
specific to a particular CSV dialect. It may be an instance of a subclass of
the :class:`Dialect` class or one of the strings returned by the
Return a writer object responsible for converting the user's data into delimited
strings on the given file-like object. *csvfile* can be any object with a
- :func:`write` method. An optional *dialect*
+ :func:`write` method. If csvfile is a file object, it should be opened with
+ newline='' [1]_. An optional *dialect*
parameter can be given which is used to define a set of parameters specific to a
particular CSV dialect. It may be an instance of a subclass of the
:class:`Dialect` class or one of the strings returned by the
A short usage example::
>>> import csv
- >>> spamWriter = csv.writer(open('eggs.csv', 'w'), delimiter=' ',
+ >>> spamWriter = csv.writer(open('eggs.csv', 'w', newline=''), delimiter=' ',
... quotechar='|', quoting=csv.QUOTE_MINIMAL)
>>> spamWriter.writerow(['Spam'] * 5 + ['Baked Beans'])
>>> spamWriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
Reading a file with an alternate format::
import csv
- with open('passwd') as f:
+ with open('passwd', newline='') as f:
reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)
for row in reader:
print(row)
The corresponding simplest possible writing example is::
import csv
- with open('some.csv', 'w') as f:
+ with open('some.csv', 'w', newline='') as f:
writer = csv.writer(f)
writer.writerows(someiterable)
import csv
csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)
- with open('passwd') as f:
+ with open('passwd', newline='') as f:
reader = csv.reader(f, 'unixpwd')
A slightly more advanced use of the reader --- catching and reporting errors::
.. rubric:: Footnotes
-.. [#] If ``newline=''`` is not specified, newlines embedded inside quoted fields
- will not be interpreted correctly. It should always be safe to specify
- ``newline=''``, since the csv module does its own universal newline handling
- on input.
+.. [1] If ``newline=''`` is not specified, newlines embedded inside quoted fields
+ will not be interpreted correctly, and on platforms that use ``\r\n`` linendings
+ on write an extra `\\r` will be added. It should always be safe to specify
+ ``newline=''``, since the csv module does its own (universal) newline handling.