Assign long integer (was: [Tutor] Calculating a math formula and finding errors)

[Jeff Shannon]

Jens Kubieziel wrote:

>On Mon, Jan 13, 2003 at 03:22:07AM -0800, Danny Yoo wrote:
>  
>
>>def factorial(z):
>>    assert z >= 0, "Invalid input: z must be nonnegative."
>>    if z == 1 or z == 0:
>>        return 1
>>    else:
>>        return z*factorial(z-1)
>>    
>>
>
>I still try to improve above mentioned function and want to extend this
>for long integers. I read that I can do this by adding an "l". But how do
>I do this with variables?
>If I'd write zL it is like a new variable. So must be another way.
>  
>

Actually, because Python will automatically convert to long integers if 
there's integer overflow, you don't need to do anything.

 >>> factorial(3)
6
 >>> factorial(10)
3628800
 >>> factorial(15)
1307674368000L
 >>>

As you can see, the final result there is a number followed by an L. 
 That means that the result is a long int, despite the fact that nothing 
in the function specifies a need to use long ints -- I've used exactly 
the same function posted here.  Python has automagically handled the 
overflow by switching to longs, without us needing to do anything.

Jeff Shannon
Technician/Programmer
Credit International