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Newsgroups: comp.lang.python
Date: Tue, 11 Sep 2012 12:13:45 -0700 (PDT)
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Subject: Re: how to get os.py to use an ./ntpath.py instead of Lib/ntpath.py
From: ruck <john.ruckstuhl@gmail.com>
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On Tuesday, September 11, 2012 12:21:24 AM UTC-7, Tim Golden wrote:
> And so it does, but you'll notice from the MSDN docs that the \\?
> syntax must be supplied as a Unicode string, which os.listdir
> will do if you pass it a Python unicode object and not otherwise:

I was saying os.listdir doesn't like the r'\\?\' prefix.
But Tim corrects me -- so yes, Steven's earler suggestion "Why don't you ju=
st prepend a '?' to paths like they tell you to?" does work, when I supply =
it in unicode.
Good:
    >>> os.listdir(u'\\\\?\\C:\\Users\\john\\Desktop\\sandbox\\goo')
   [u'voo...']
Bad:
    >>> os.listdir('\\\\?\\C:\\Users\\john\\Desktop\\sandbox\\goo')

    Traceback (most recent call last):
      File "<pyshell#3>", line 1, in <module>
        os.listdir('\\\\?\\C:\\Users\\john\\Desktop\\sandbox\\goo')
    WindowsError: [Error 123] The filename, directory name, or volume label=
 syntax is incorrect: '\\\\?\\C:\\Users\\john\\Desktop\\sandbox\\goo/*.*'

Thanks to both of you for taking the time to teach.

BTW, when I posted the original, I was trying to supply my own customized n=
tpath module, and I was really puzzled as to why it wasn't getting picked u=
p! According to sys.path I expected my custom ntpath.py to be chosen, inste=
ad of the standard Lib/ntpath.py.

Now I guess I understand why.  I moved Lib/ntpath.* out of the way, and lea=
rned that during initialization, Python is importing "site" module, which i=
s importing "os" which is importing "ntpath" -- before my dir is added to s=
ys.path.  So later when I import os, it and ntpath have already been import=
ed, so Python doesn't attempt a fresh import.

To get my custom ntpath.py honored, need to RELOAD, like:
  import os
  import ntpath
  reload(ntpath)
  print 'os.walk(\'goo\') with isdir override in custom ntpath'
  for root, dirs, files in os.walk('goo'):
      print root, dirs, files

where the diff betw standard ntpath.py and my ntpath.py are:
  14c14,19
  < from genericpath import *
  ---
  > from genericpath import *
  >
  > def isdir(s):
  >     return genericpath.isdir('\\\\?\\' + abspath(s + '\\'))
  > def isfile(s):
  >     return genericpath.isfile('\\\\?\\' + abspath(s + '\\'))

I'm not sure how I could have known that ntpath was already imported, since=
 *I* didn't import it, but that was the key to my confusion.

Thanks again for the help.
John