How do I get str.translate to work with Unicode strings?
python, string, unicode
Solution
The Unicode version of translate requires a mapping from Unicode ordinals (which you can retrieve for a single character with `ord`) to Unicode ordinals. If you want to delete characters, you map to `None`.
I changed your function to build a dict mapping the ordinal of every character to the ordinal of what you want to translate to:
def translate_non_alphanumerics(to_translate, translate_to=u'_'):
not_letters_or_digits = u'!"#%\'()*+,-./:;<=>?@[\]^_`{|}~'
translate_table = dict((ord(char), translate_to) for char in not_letters_or_digits)
return to_translate.translate(translate_table)
>>> translate_non_alphanumerics(u'<foo>!')
u'_foo__'
edit: It turns out that the translation mapping must map from the Unicode ordinal (via `ord`) to either another Unicode ordinal, a Unicode string, or None (to delete). I have thus changed the default value for `translate_to` to be a Unicode literal. For example:
>>> translate_non_alphanumerics(u'<foo>!', u'bad')
u'badfoobadbad'
Problem
I have the following code: ``` import string def translate_non_alphanumerics(to_translate, translate_to='_'): not_letters_or_digits = u'!"#%\'()*+,-./:;<=>?@[\]^_`{|}~' translate_table = string.maketrans(not_letters_or_digits, translate_to *len(not_letters_or_digits)) return to_translate.translate(translate_table) ``` Which works great for non-unicode strings: ``` >>> translate_non_alphanumerics('<foo>!') '_foo__' ``` But fails for unicode strings: ``` >>> translate_non_alphanumerics(u'<foo>!') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 5, in translate_non_alphanumerics TypeError: character mapping must return integer, None or unicode ``` I can't make any sense of the paragraph on "Unicode objects" in the Python 2.6.2 docs for the str.translate() method. How do I make this work for Unicode strings?