[PyQt] Re: Bug in QString comparison
phil at riverbankcomputing.com
Tue Sep 16 21:54:09 BST 2008
On Wed, 10 Sep 2008 01:51:54 +0200, Giovanni Bajo <rasky at develer.com>
> Hello Phil,
> this looks weird to me (using sip 4.7.6, PyQt 4.4.2, Qt 4.4.0):
> $ python
> Python 2.5.2 (r252:60911, May 7 2008, 15:21:12)
> [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> from PyQt4.Qt import *
>>>> "a" == QString("a")
>>>> u"a" == QString(u"a")
>>>> a = u"\u30b5"
>>>> b = QString(a)
>>>> a == b
> Why does the equality operator returns False?
a is converting b to a string because QString supports the buffer protocol.
That conversion is done using the default codec which is normally ascii. If
QString didn't support the buffer protocol then I think Python would then
go on to try b == a, which would work.
b == a works as expected because b is converting a to a QString first.
> Moreover: I can't appear to be able to print the QString:
>>>> print a
>>>> print b
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> UnicodeEncodeError: 'ascii' codec can't encode character u'\u30b5' in
> position 0: ordinal not in range(128)
It's the same cause - the default codec is ascii.
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