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ASCII transliterations of Unicode text

Project description

It often happens that you have text data in Unicode, but you need to represent it in ASCII. For example when integrating with legacy code that doesn’t support Unicode, or for ease of entry of non-Roman names on a US keyboard, or when constructing ASCII machine identifiers from human-readable Unicode strings that should still be somewhat intelligeble (a popular example of this is when making an URL slug from an article title).

In most of these examples you could represent Unicode characters as ??? or \15BA\15A0\1610, to mention two extreme cases. But that’s nearly useless to someone who actually wants to read what the text says.

What Unidecode provides is a middle road: function unidecode() takes Unicode data and tries to represent it in ASCII characters (i.e., the universally displayable characters between 0x00 and 0x7F), where the compromises taken when mapping between two character sets are chosen to be near what a human with a US keyboard would choose.

The quality of resulting ASCII representation varies. For languages of western origin it should be between perfect and good. On the other hand transliteration (i.e., conveying, in Roman letters, the pronunciation expressed by the text in some other writing system) of languages like Chinese, Japanese or Korean is a very complex issue and this library does not even attempt to address it. It draws the line at context-free character-by-character mapping. So a good rule of thumb is that the further the script you are transliterating is from Latin alphabet, the worse the transliteration will be.

Note that this module generally produces better results than simply stripping accents from characters (which can be done in Python with built-in functions). It is based on hand-tuned character mappings that for example also contain ASCII approximations for symbols and non-Latin alphabets.

This is a Python port of Text::Unidecode Perl module by Sean M. Burke <>.

Module content

The module exports a single function that takes an Unicode object (Python 2.x) or string (Python 3.x) and returns a string (that can be encoded to ASCII bytes in Python 3.x):

>>> from unidecode import unidecode
>>> unidecode(u'ko\u017eu\u0161\u010dek')
>>> unidecode(u'30 \U0001d5c4\U0001d5c6/\U0001d5c1')
'30 km/h'
>>> unidecode(u"\u5317\u4EB0")
'Bei Jing '

A utility is also included that allows you to transliterate text from the command line in several ways. Reading from standard input:

$ echo hello | unidecode

from a command line argument:

$ unidecode -c hello

or from a file:

$ unidecode hello.txt

The default encoding used by the utility depends on your system locale. You can specify another encoding with the -e argument. See unidecode –help for a full list of available options.


Nothing except Python itself.

You need a Python build with “wide” Unicode characters (also called “UCS-4 build”) in order for unidecode to work correctly with characters outside of Basic Multilingual Plane (BMP). Common characters outside BMP are bold, italic, script, etc. variants of the Latin alphabet intended for mathematical notation. Surrogate pair encoding of “narrow” builds is not supported in unidecode.

If your Python build supports “wide” Unicode the following expression will return True:

>>> import sys
>>> sys.maxunicode > 0xffff

See PEP 261 for details regarding support for “wide” Unicode characters in Python.


To install Unidecode from the source distribution and run unit tests, use these commands:

$ python install
$ python test


You can get the latest development version of Unidecode with:

$ git clone


Questions, bug reports, useful code bits, and suggestions for Unidecode should be sent to

Project details

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