os.path.walk oddity

[Simon Callan]

For reasons to complicated to go into here, I am having to rearrange a
source tree. Basically every .c file has to be moved into a
subdirectory called 'c', with the extension removed, while .h files
are moved to a 'h' directory. I.e
fred/jim.c -> fred.c.jim
fred/sheila.h -> fred.h.sheila

After figuring out how to stop os.path.walk crashing due to renaming
files, I ended up with the following:

=====

#!/usr/bin/env python

import os

def rename(dir, root, ext):
  new_dir = os.path.join(dir, ext)
  if not os.path.exists(new_dir):
    os.mkdir(new_dir)
  o_file = os.path.join(dir, root) + '.' + ext
  n_file = os.path.join(dir, ext, root)
  print "%s -> %s" % (o_file, n_file)
  os.rename(o_file, n_file)

def toRiscos(arg, dir, names):
  temp = names
  count = 0
  for file in temp:
    root, ext = os.path.splitext(file)
    if ext == '.c':
      del names[count]
      rename(dir, root, 'c')
    elif ext == '.h':
      del names[count]
      rename(dir, root, 'h')
    count += 1

os.path.walk('.', toRiscos, None)

=====

However, there is one problem. If I run the above on the python 2.0
source directory, it takes 3 runs of the programme to completely
convert the tree.

Can anyone explain why this is?

Simon

-- 
http://www.callan.demon.co.uk/simon/