How to Sort Unicode Strings Alphabetically in Python

How do I sort unicode strings alphabetically in Python?

IBM's ICU library does that (and a lot more). It has Python bindings: PyICU.

Update: The core difference in sorting between ICU and locale.strcoll is that ICU uses the full Unicode Collation Algorithm while strcoll uses ISO 14651.

The differences between those two algorithms are briefly summarized here: http://unicode.org/faq/collation.html#13. These are rather exotic special cases, which should rarely matter in practice.

>>> import icu # pip install PyICU
>>> sorted(['a','b','c','ä'])
['a', 'b', 'c', 'ä']
>>> collator = icu.Collator.createInstance(icu.Locale('de_DE.UTF-8'))
>>> sorted(['a','b','c','ä'], key=collator.getSortKey)
['a', 'ä', 'b', 'c']

How to sort unicode strings alphabetically in Common Lisp?

If you use SBCL, you have integrated support for unicode.

String operations

Try to sort with unicode< instead of string-lessp.

Sorting strings with accented characters in python

I finally chose to strip diacritics and compare the stripped version of the strings so that I don't have to add the PyICU dependency.

How to sort a list with an exception in Python

Here is a simple solution based on the Turkish alphabet:

alphabet = "abcçdefgğhıijklmnoöprsştuüvyz"
words = ["merhaba", "aşk", "köpek", "Teşekkürle"]

sorted_words = sorted(words, key=lambda word: tuple(alphabet.index(c) for c in word.lower()))

This code is able to sort words using the lexicographic order. It also works with words containing capital letters.

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