Limitation of os.walk

[Terry Reedy]

On 5/11/2010 3:49 PM, kj wrote:
>
>
>
> I want implement a function that walks through a directory tree
> and performs an analsysis of all the subdirectories found.  The
> task has two essential requirements that, AFAICT, make it impossible
> to use os.walk for this:
>
> 1. I need to be able to prune certain directories from being visited.
>
> 2. The analysis on each directory can be performed only after it
>     has been performed on all its subdirectories.
>
> Unless I'm missing something, to do (1), os.walk must be run with
> topdown=True, whereas to do (2) it must be run with topdown=False.
>
> Is there a work around that I'm missing?

(I was going to say, 'Copy the code from os.py and revise to suit' -- 
but I see this has been posted since I wrote it ;-)

> PS: I never understood why os.walk does not support hooks for key
> events during such a tree traversal.

Either 1) it is intentionally simple, with the expectation that people 
would write there own code for more complicated uses or 2) no one has 
submitted a 'full-featured' version or 3) both.

If os.walk were rewritten, it should be as an iterator (generator). 
Directory entry and exit functions could still be added as params.

Terry Jan Reedy