Iterative vs. Recursive coding

John Nagle nagle at animats.com
Sat Aug 21 08:37:12 CEST 2010


On 8/20/2010 1:17 PM, John Bokma wrote:
> John Nagle<nagle at animats.com>  writes:
>
>>      Python does not do tail recursion, so using recursion
>> where iteration could do the job is generally a bad idea.  Scheme, on
>> the other hand, always does tail recursion where possible.
>
> I think you mean tail recursion optimization / elimination.
> Python does tail recursion:

    Not very well.

     def cnt(n) :
         if n > 0 :
             cnt(n-1)


This will work for up to cnt(998), but at cnt(999), CPython
reports "RuntimeError: maximum recursion depth exceeded."

Yes, you can increase the recursion depth, but that case
shouldn't be compiled to recursion at all.

				John Nagle



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