Python, Unicode, and the Windows console
When I try to print a Unicode string in a Windows console, I get a UnicodeEncodeError: 'charmap' codec can't encode character .... error. I assume this is because the Windows console does not accept Unicode-only characters. What's the best way around this? Is there any way I can make Python automatically print a ? instead of failing in this situation?
Edit: I'm using Python 2.5.
Note: @LasseV.Karlsen answer with the checkmark is sort of outdated (from 2008). Please use the solutions/answers/suggestions below with care!!
@JFSebastian answer is more relevant as of today (6 Jan 2016).
Note: This answer is sort of outdated (from 2008). Please use the solution below with care!!
Here is a page that details the problem and a solution (search the page for the text Wrapping sys.stdout into an instance):
PrintFails - Python Wiki
Here's a code excerpt from that page:
$ python -c 'import sys, codecs, locale; print sys.stdout.encoding;
sys.stdout = codecs.getwriter(locale.getpreferredencoding())(sys.stdout);
line = u"u0411n"; print type(line), len(line);
sys.stdout.write(line); print line'
UTF-8
<type 'unicode'> 2
Б
Б
$ python -c 'import sys, codecs, locale; print sys.stdout.encoding;
sys.stdout = codecs.getwriter(locale.getpreferredencoding())(sys.stdout);
line = u"u0411n"; print type(line), len(line);
sys.stdout.write(line); print line' | cat
None
<type 'unicode'> 2
Б
Б
There's some more information on that page, well worth a read.
Update: Python 3.6 implements PEP 528: Change Windows console encoding to UTF-8: the default console on Windows will now accept all Unicode characters. Internally, it uses the same Unicode API as the win-unicode-console package mentioned below. print(unicode_string) should just work now.
I get a UnicodeEncodeError: 'charmap' codec can't encode character... error.
The error means that Unicode characters that you are trying to print can't be represented using the current ( chcp ) console character encoding. The codepage is often 8-bit encoding such as cp437 that can represent only ~0x100 characters from ~1M Unicode characters:
>>> u"N{EURO SIGN}".encode('cp437')
Traceback (most recent call last):
...
UnicodeEncodeError: 'charmap' codec can't encode character 'u20ac' in position 0:
character maps to I assume this is because the Windows console does not accept Unicode-only characters. What's the best way around this?
Windows console does accept Unicode characters and it can even display them (BMP only) if the corresponding font is configured . WriteConsoleW() API should be used as suggested in @Daira Hopwood's answer. It can be called transparently ie, you don't need to and should not modify your scripts if you use win-unicode-console package:
T:> py -mpip install win-unicode-console
T:> py -mrun your_script.py
See What's the deal with Python 3.4, Unicode, different languages and Windows?
Is there any way I can make Python automatically print a ? instead of failing in this situation?
If it is enough to replace all unencodable characters with ? in your case then you could set PYTHONIOENCODING envvar:
T:> set PYTHONIOENCODING=:replace
T:> python3 -c "print(u'[N{EURO SIGN}]')"
[?]
In Python 3.6+, the encoding specified by PYTHONIOENCODING envvar is ignored for interactive console buffers unless PYTHONLEGACYWINDOWSIOENCODING envvar is set to a non-empty string.
Despite the other plausible-sounding answers that suggest changing the code page to 65001, that does not work. (Also, changing the default encoding using sys.setdefaultencoding is not a good idea.)
See this question for details and code that does work.
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