Python library for converting between a string of ASCII and Unicode chars maintaining readability
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Latest commit 41b186b Sep 30, 2015 @potrebic potrebic Merge pull request #14 from box/py35-and-pypy26
Add support for py35, pypy26



RotUnicode is a Python library that can convert a string containing ASCII characters to a string with non-ASCII characters without losing readability.

>>> 'Hello World!'.encode('rotunicode')
Ĥȅľľő Ŵőŕľď!
>>> 'Ĥȅľľő Ŵőŕľď!'.decode('rotunicode')
Hello World!

In the above example, the 'Hello World' string has all ASCII characters. Encoding it with RotUnicode gives you 'Ĥȅľľő Ŵőŕľď' which reads like 'Hello World' but has all non-ASCII characters.

Why is this named RotUnicode?

RotUnicode stands for rotate-to-unicode. Or rotten-unicode for those who have nightmares about Unicode. It was inspired by Rot13.

Supported Characters

RotUnicode converts lower case and upper case characters of the English alphabet and digits 0 to 9 to non-ASCII characters. All characters that are outside this range are left as is.

>>> 'हेलो World!'.encode('rotunicode')
हेलो Ŵőŕľď!
>>> 'हेलो Ŵőŕľď!'.decode('rotunicode')
हेलो World!


To install, simply:

pip install rotunicode


>>> from rotunicode import ruencode
>>> ruencode('Hello World!')
Ĥȅľľő Ŵőŕľď!
>>> rudecode('Ĥȅľľő Ŵőŕľď!')
Hello World!

As a Codec

In Python 2, RotUnicode can also be used as a codec, but it must first be registered with the codecs library. This allows python to know what functions to call to encode or decode a string using RotUnicode.

>>> import codecs
>>> from rotunicode import RotUnicode
>>> codecs.register(RotUnicode.search_function)
>>> 'Hello World!'.encode('rotunicode')
Ĥȅľľő Ŵőŕľď!

Command Line

Installing RotUnicode also includes a command line tool.

$ rotunicode "Hello World"
Ĥȅľľő Ŵőŕľď!
$ rotunicode -d "Ĥȅľľő Ŵőŕľď!"
Hello World!
$ echo "Hello World!" > hello.txt
$ rotunicode -f hello.txt
Ĥȅľľő Ŵőŕľď!
$ cat hello.txt | rotunicode -f
Ĥȅľľő Ŵőŕľď!

Why should I use RotUnicode?

RotUnicode it extremely helpful in testing because it reduces the friction for developers to test with non-ASCII strings. Imagine for example that you have a class to represent a contact for your address book application:

class Contact(object):

    def __init__(self, first_name, last_name):
        super(Contact, self).__init__()
        self.first_name = first_name
        self.last_name = last_name

    def display_name(self):
        return '{} {}'.format(self.first_name, self.last_name)

Most developers would test this as follows:

from unittest import TestCase
from contact import Contact

class ContactTests(TestCase):

    def test_display_name(self):
        contact = Contact('John', 'Doe’)
        self.assertEqual('John Doe', contact.display_name()))

This test is good. But it is going to miss catching problems in the code with non-ASCII characters. Requiring developers to remember how to type non-ASCII characters is not practical. With RotUnicode, this is super easy:

from unittest import TestCase
from contact import Contact

class ContactTests(TestCase):

    def test_display_name_with_ascii_name(self):
        contact = Contact(u'John', u'Doe')
        self.assertEqual(u'John Doe', contact.display_name())

    def test_display_name_with_non_ascii_name(self):
        contact = Contact(ruencode(u'John'), ruencode(u'Doe'))
        self.assertEqual(ruencode(u'John Doe'), contact.display_name())

This is an example of a bug in Python (issue18695) with non-ASCII characters -

>>> import os, errno
>>> name = 'foo'.encode('rotunicode')
>>> os.mkdir(name)
>>> print(name)
>>> os.path.exists(name)
>>> os.statvfs(name)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-2:
ordinal not in range(128)




Create a virtual environment and install packages:

mkvirtualenv rotunicode
pip install -r requirements-dev.txt


Run all tests using:


The tox tests include code style checks via pep8 and pylint.

The tox tests are configured to run on Python 2.6, 2.7, 3.3, 3.4, 3.5, and PyPy 2.6.

Copyright and License

Copyright 2015 Box, Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.