On 12/10/2010 5:20 AM, frank cui wrote:
> Hi all,
>
> I'm a novice learner of python and get caught in the following trouble
> and hope experienced users can help me solve it:)
>
> Code:
> -----------------------------------------------------------------------
> $ cat Muffle_ZeroDivision.py
> #!/usr/bin/env python
>
> class MuffledCalculator:
> muffled = False
> def clac(self,expr):
> try:
> return eval(expr)
> except:
> if self.muffled:
> print 'Division by zero is illegal'
> else:
> raise
> --------------------------------------------------------------------------
>
> $ python
> Python 2.7 (r27:82500, Sep 16 2010, 18:03:06)
> [GCC 4.5.1 20100907 (Red Hat 4.5.1-3)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import Muffle_ZeroDivision
>>>> calc = Muffle_ZeroDivision.MuffledCalculator()
>>>> calc = ('10/2')
>>>> calc = Muffle_ZeroDivision.MuffledCalculator()
>>>> calc('10/2')
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> AttributeError: MuffledCalculator instance has no __call__ method
>
> ----------------------------------------------------------------------------
>
> There is an AttributeError that this instance doesn't have the __call__
> method, so how to add this kind of method to my instance?
>
> Thanks a lot in advance.
>
> Regards
> Frank.Cui
>
Try renaming your .calc() method to .__call__(). That way the method
will be called when you perform a function call on an instance.
regards
Steve
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