pythonic tree-walking idioms

[Tim Peters]

[Fredrik Lundh]
> os.path.walk is pretty unpythonic, imo [1].

Mine too, and, luckily for us <wink>, also Guido's:  last time this came up,
he said he considers os.path.walk to be a youthful indiscretion.  I'm sure it
will never go away, but I never steer people toward it either.

> using an iterator-style "walker" object is usually both faster and
> more convenient.

I always do it by hand!

    pending = [dir]
    while pending:
        dir = pending.pop()
        for shortname in os.listdir(dir):
            path = os.path.join(dir, shortname)
            if os.path.isdir(path):
                pending.append(path)
            # and whatever processing needs to be done
            # goes here

See Neil Schemenauer's post to see how that can be used almost vertabim to
create a generator for producing the paths via the 2.2 iterator protocol (+
his generator patch).  Sweet.