AttributeError: ClassA instance has no attribute '__len__'
wittempj@hotmail.com
martin.witte at gmail.com
Wed Mar 30 15:01:06 EST 2005
The most simple way to get this error I can think of is like this. It
happens because len does not know how to calculate the lenght of this
object.
-class classA:
- def __init__(self):
- pass
-a = classA()
-print len (a)
Traceback (most recent call last):
File "./test.py", line 10, in ?
print len (a)
AttributeError: classA instance has no attribute '__len__'
You can fix it by adding a __len__ method:
class classA:
def __init__(self):
pass
def __len__(self):
return 0
a = classA()
print len (a)
See http://docs.python.org/ref/sequence-types.html
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