On 01/-10/-28163 02:59 PM, 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?
Your problem is that you defined a clac() method, but never call it. So
instead of calc('10/2') you need
calc.clac("10/2")
I'm not sure why you have such a confusing name, however.
DaveA
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