Re: Weirdness comparing strings

Instance comparison is not necessarily the same as string comparison. Neither __str__ nor __repr__ are implicitly used at all for comparison.

In fact, by default a pair of instances are not equal unless they are the same object. To define comparison to mean something, you need to define __cmp__ or __eq__.

Trivial example of default comparison:

>>> class C:
.... pass
....
>>> c = C()
>>> d = C()
>>> c==d
False
>>> c==c
True

See http://docs.python.org/ref/customization.html for more details.

Ken


Mr.SpOOn wrote:
Hi,
I have this piece of code:

class Note():
...
...
def has_the_same_name(self, note):
return self == note

def __str__(self):
return self.note_name + accidentals[self.accidentals]

__repr__ = __str__

if __name__ == '__main__':
n = Note('B')
n2 = Note('B')
print n
print n2
print n.has_the_same_name(n2)

I'd expect to get "True", because their string representation is
actually the same, instead the output is:

B
B
False

I think I'm missing something stupid. Where am I wrong?
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