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Python 3 like CSV module for Python 2

Project description


csv342 is a Python module similar to the the csv module in the standard
library. Under Python 3, it just calls the standard csv module. Under
Python 2, it provides a Python 3 like interface to reading and writing CSV
files, in particular concerning non ASCII characters.

It is distributed under the BSD license. The source code is available from


To install, simply run::

$ pip install --upgrade csv342

Alternatively you can download the distributin archive from, unpack it and copy ```` into
your application path.


First, consider changing all string literals in you source code to
``unicode`` instead of ``str`` under Python 2 using to avoid the
messy ``u`` string prefix.

>>> from __future__ import unicode_literals

The following examples assume you did that, making your Python 2 code look
like Python 3 even more.

Once you import ``csv342`` using

>>> import csv342 as csv

your code can call CSV functions the same way independent of whether it runs
under Python 2 or 3. First, let's write a few test data to a ``io.StringIO``:

>>> import io
>>> csv_stream = io.StringIO()
>>> csv_writer = csv.writer(csv_stream)
>>> csv_writer.writerow(['a', 'b'])
>>> csv_writer.writerow(['1', '"x"'])
>>> csv_content = csv_stream.getvalue()
>>> str(csv_content)

To read data from a ``io.StringIO`` use:

>>> csv_stream = io.StringIO('a,b\r\n1,"""x"""\r\n')
>>> csv_reader = csv.reader(csv_stream)
>>> for row in csv_reader:
>>> print(row)

To read a UTF-8 encoded CSV file with non ASCII characters use:

>>> csv_path = os.path.join('test', 'utf-8.csv')
>>> with, encoding='utf-8', newline='') as csv_file:
>>> csv_reader = csv.reader(csv_file, delimiter=',')
>>> for row in csv_reader:
>>> print('row {0:d}: data={1}'.format(csv_reader.line_num, row))


* Supports Python 2's ``unicode`` strings.
* Provides ``reader``, ``writer``, ``DictReader`` and ``DictWriter``.
* Supports reading and writing with files, ``io.StringIO`` etc.
* Rejects attempts to read or write with ``cStringIO`` or
``StringIO.StringIO`` (which do not really work with ``unicode``);
use ``io.StringIO`` instead.


* All limitations of the standard ``csv`` module apply.
* Uses the standard ``csv.Sniffer`` under Python 2.
* Requires Python 2.6 or later.


Processing a CSV with Python 2 using ``csv342`` is about 30% slower than
processing it with Python 3. This is probably due the fact that under Python
2 there is an intermediate translation to UTF-8 using pure Python code while
in Python 3 uses mostly native code.

Provided you have both Python 2 and 3 installed on the same machine, you can
test this yourself running::

python3 test/
python2 test/

On an ancient laptop with a core 2 duo Intel CPU and Ubuntu 14.04, this takes
10.2 seconds respectively 13.6 seconds.


Copyright (c) 2016-2018, Thomas Aglassinger
All rights reserved.

Distributed under the BSD License. For more information, see LICENSE.txt.

Version history

Version 1.0.0, 2018-04-02
* Fixed ``DictReader`` so that it can now read from a list of lines
(`issue #1 <>`_, contributed by
Lucas Wiman).
* Fixed ``AttributeError`` in ``StringIO`` test (contributed by Lucas Wiman).

Version 0.2, 2016-04-17
* Fixed version number when running under Python 3.
* Fixed helper constant ``IS_PYHTON2`` which always was ``False``.
* Added remaining symbols from Python 2's ``csv`` module.

Version 0.1, 2016-04-16
* Initial release.

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