Question

This is the code i used. Why cant os walk handle ?

import os, re

cwd = os.getcwd() 
directory= 'Box II'
dirpattern = re.compile(r'^.*?\\'+directory+'.*?', re.M)

for root, dirs, files in os.walk(os.path.abspath(cwd)):
    if dirpattern.search(root):
        match = dirpattern.search(root)
        match=match.group(0)

print match #OUTPUT = D:\dir1\dir2\dir3 (the directory i searched for)

for root, dirs, files in os.walk(os.path.abspath(match)):
    print files #OUTPUT = nothing

why cant i use the matched folder for a new os.walk loop?

Answer 1

I think you want to use a generator to yield each match so that you can walk over the things that match your expression. Here is a snippet of code that I use regularly.

import os, fnmatch

#
# This wrapper for os.walk is based on Python Cookbook, 2.16.
# Added the exclude_dirs named parameter so that we can skip svn folders.
# Added the yield_files named parameter so that we can return only folders.
#

def walk_file_system (root, patterns='*', single_level=False, yield_folders=False, yield_files=True, exclude_dirs='.svn'):
    # Expand patterns from semicolon-separated string to list
    patterns = patterns.split (';')
    exclude_dirs = exclude_dirs.split (';')
    for path, subdirs, files in os.walk (root):
        for exclude_dir in exclude_dirs:
            for dir in subdirs:
                if fnmatch.fnmatch (dir, exclude_dir):
                    subdirs.remove(dir)
        fsnodes = []
        if yield_folders:
            fsnodes.extend(subdirs)
        if yield_files:
            fsnodes.extend(files)
        fsnodes.sort ( )
        for name in fsnodes:
            for pattern in patterns:
                if fnmatch.fnmatch (name, pattern):
                    yield os.path.join (path, name)
                    break
        if single_level:
            break

You can use it like this.

def walk_file_system_test():
    #patterns='*', single_level=False, yield_folders=False, yield_files=True, exclude_dirs='.svn'):
    print "Walk current directory with function defaults."
    for fsnode in walk_file_system(os.getcwd()):
        print fsnode

    #patterns='*', single_level=False, yield_folders=True, yield_files=True, exclude_dirs='.svn'):
    print "Walk current directory with yield_folders=True."
    for fsnode in walk_file_system(os.getcwd(), yield_folders=True):
        print fsnode

    #patterns='*', single_level=False, yield_folders=True, yield_files=False, exclude_dirs='.svn'):
    print "Walk current directory with yield_folders=True, yield_files=False."
    for fsnode in walk_file_system(os.getcwd(), yield_folders=True, yield_files=False):
        print fsnode

    #patterns='*', single_level=False, yield_folders=True, yield_files=False, exclude_dirs='.svn'):
    print "Walk current directory with yield_folders=True, yield_files=False, exclude_dirs='.svn;temp'."
    for fsnode in walk_file_system(os.getcwd(), yield_folders=True, yield_files=False, exclude_dirs='.svn;temp'):
        print fsnode

Hope this helps.
It should be fairly simple for you to replace the fnmatch with re.