[Tutor] self keyword in recursive function

[Ritwik Raghav]

Peter Otten wrote:

>Ritwik Raghav wrote:
>
>> I joined the topcoder community tomorrow and tried solving the
>> PersistentNumber problem:
>> "Given a number x, we can define p(x) as the product of the digits of x.
>> We can then form a sequence x, p(x), p(p(x))... The persistence of x is
>> then defined as the index (0-based) of the first single digit number in
>> the sequence. For example, using 99, we get the sequence 99, 9*9 = 81,
8*1
>> = 8. Thus, the persistence of 99 is 2. You will be given n, and you must
>> return its persistence."
>>
>> It asks to define a function def getPersistence(self, n). I solved the
>> problem in IDLE. My code is:
>>
>> def getPersistence(n,count = 0):
>>     product = 1
>>     if len(str(n)) == 1:
>>         return count
>>     else:
>>         a = str(n)
>>         for i in range(len(a)):
>>             product *= int(a[i])
>>         count += 1
>>         return getPersistence(product,count)
>>
>> Now plz help me to convert the above code in specified format. Or help me
>> understand how to recreate the function as specified.
>
>The "topcoder" site is probably infested with the world view of Java where
>every function is a method inside a class. You may have to wrap your code
>into something like
>
>class PersistentNumber:
>    def getPersistence(self, n, count=0):
>        ... # your code with a minor change (*)
>
>
>(*) Inside the method the recursive call becomes
>
>    self.getPersistence(product, count)
>
>instead of just
>
>    getPersistence(product, count)

It has again given some error I do not understand. This time my code is:

count = 0
def getPersistence(self,n):
    product = 1
    if len(str(n)) == 1:
        return self.count
    else:
        a = str(n)
        for i in a:
            product *= int(i)
        self.count += 1
        return self.getPersistence(product)

and the error is:

Correct Return Value: No

Answer check result:
Result must be not null.

Execution Time: 0.017s

Peak memory used: 24.551MB

abnormal termination (exit 1)

Standard Output:


Standard Error:
Traceback (most recent call last):
  File "Wrapper.py", line 182, in <module>
AttributeError: 'module' object has no attribute 'PersistentNumber'


I do not understand what it is trying to tell me? I tried to test it for 99.

-- 
Ritwik Raghav
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