Profiling, recursive func slower than imperative, normal?

[Robert Bossy]

Gabriel Genellina wrote:
> En Wed, 16 Apr 2008 17:53:16 -0300, <s0suk3 at gmail.com> escribió:
>
>   
>> On Apr 16, 3:27 pm, Jean-Paul Calderone <exar... at divmod.com> wrote:
>>
>>     
>>> Any function can be implemented without recursion, although it isn't
>>> always easy or fun.
>>>
>>>       
>> Really? I'm curious about that, I can't figure out how that would
>> work. Could give an example? Say, for example, the typical: walking
>> through the file system hierarchy (without using os.walk(), which uses
>> recursion anyway!).
>>     
>
> Use a queue of pending directories to visit:
>
> start with empty queue
> queue.put(starting dir)
> while queue is not empty:
>    dir = queue.get()
>    list names in dir
>    for each name:
>      if is subdirectory: queue.put(name)
>      else: process file
>   
Hi,

In that case, I'm not sure you get any performance gain since the queue 
has basically the same role as the stack in the recursive version. A 
definitive answer calls for an actual test, though.

Anyway if you want to process the tree depth-first, the queue version 
falls in the "not fun" category.

Cheers,
RB