Firstly, is there one?
If not, is there a nice way to force something like
print '%s' % obj
to call obj.__unicode__ instead of obj.__str__?
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3 Answers
Just use a unicode format string, rather than having a byte string in that role:
>>> class X(object):
... def __str__(self): return 'str'
... def __unicode__(self): return u'unicode'
...
>>> x = X()
>>> print u'%s' % x
unicode
4 Comments
Mike Graham
Having
__unicode__ return a bytestring and printing a unicode object make awful examples.
Alex Martelli
@Mike, agreed on the
return issue -- fixed that typo. Strong disagreement on the print: on a decent platform, sys.stdout.encoding is set and the print will work perfectly -- while you're guessing blindly at the some_encoding to use (if it's not on sys.stdout how are you gonna guess it, pray?).
habnabit
on what "decent platform" does
python -c 'print u"\xff"' >some_file not raise a UnicodeEncodeError?Alex Martelli
@Aaron, if
sys.stdout.encoding is None (or 'ascii', etc), which would be the case in your example, of course printing characters not renderable in that encoding is an error -- just like @Mike's code would be if the mysterious some_encoding he uses but never specifies was similarly non-universal (or a mismatch for sys.stdout.encoding, which it completely ignores).No. It wouldn't make sense for this to be the case.
print (u"%s" % obj).encode(some_encoding) will use obj.__unicode__.
1 Comment
Alex Martelli
Hate the idea of blindly guessing at the
some_encoding as this answer would force one to do -- a decent platform will set sys.stdout.encoding so a plain print will work perfetly, if yours doesn't you must wrap sys.stdout into a wrapper which sets the encoding, in one place (then you can use print as is only proper and decent!), rather than strewing such guesses all over the furniture (what a horrible way to program).Firstly, is there one?
Sure (sort of). A unicode format string will convert the format values to unicode, implying that obj.__unicode__ will be called (reference).
u'this is a %s' % ('unicode string')
Aside from the above, there's no particular reason why you couldn't be explicit:
print '%s' % (unicode(obj))
6 Comments
Mike Graham
print '%s' % unicode(obj) isn't really explicit. It implicitly upconverts a str into a unicode when the % applies, which is among the uglier things that Python does.
mpen
Stumbled across this a few seconds later. I guess this works for me!
Alex Martelli
...and it relies on
printing a unicode string exactly like my much reviled, much-downvoted, and much-earlier answer -- seeing this one upvoted instead could confirm suspicion that the downvoters are in fact intent on a personal vendetta, not a technical objection, whatever mealy-mouthed words they may try to dress it up in;-).
Seth
@Alex - I didn't realize how close my answer was until after I posted it ... you may be right :)
Alex Martelli
@Mark, indeed I imagine you didn't, since I see you accepted it -- thanks!-)
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