parameters: (top, topdown=True, onerror=None, followlinks=False)
docstring: Directory tree generator.
  
      For each directory in the directory tree rooted at top (including top
      itself, but excluding '.' and '..'), yields a 3-tuple
  
          dirpath, dirnames, filenames
  
      dirpath is a string, the path to the directory.  dirnames is a list of
      the names of the subdirectories in dirpath (excluding '.' and '..').
      filenames is a list of the names of the non-directory files in dirpath.
      Note that the names in the lists are just names, with no path components.
      To get a full path (which begins with top) to a file or directory in
      dirpath, do os.path.join(dirpath, name).
  
      If optional arg 'topdown' is true or not specified, the triple for a
      directory is generated before the triples for any of its subdirectories
      (directories are generated top down).  If topdown is false, the triple
      for a directory is generated after the triples for all of its
      subdirectories (directories are generated bottom up).
  
      When topdown is true, the caller can modify the dirnames list in-place
      (e.g., via del or slice assignment), and walk will only recurse into the
      subdirectories whose names remain in dirnames; this can be used to prune
      the search, or to impose a specific order of visiting.  Modifying
      dirnames when topdown is false is ineffective, since the directories in
      dirnames have already been generated by the time dirnames itself is
      generated.
  
      By default errors from the os.listdir() call are ignored.  If
      optional arg 'onerror' is specified, it should be a function; it
      will be called with one argument, an os.error instance.  It can
      report the error to continue with the walk, or raise the exception
      to abort the walk.  Note that the filename is available as the
      filename attribute of the exception object.
  
      By default, os.walk does not follow symbolic links to subdirectories on
      systems that support them.  In order to get this functionality, set the
      optional argument 'followlinks' to true.
  
      Caution:  if you pass a relative pathname for top, don't change the
      current working directory between resumptions of walk.  walk never
      changes the current directory, and assumes that the client doesn't
      either.
  
      Example:
  
      import os
      from os.path import join, getsize
      for root, dirs, files in os.walk('python/Lib/email'):
          print root, "consumes",
          print sum([getsize(join(root, name)) for name in files]),
          print "bytes in", len(files), "non-directory files"
          if 'CVS' in dirs:
              dirs.remove('CVS')  # don't visit CVS directories
docstring_summary: Directory tree generator.
docstring_tokens: Directory tree generator .
function: def walk(top, topdown=True, onerror=None, followlinks=False):
      """Directory tree generator.
  
      For each directory in the directory tree rooted at top (including top
      itself, but excluding '.' and '..'), yields a 3-tuple
  
          dirpath, dirnames, filenames
  
      dirpath is a string, the path to the directory.  dirnames is a list of
      the names of the subdirectories in dirpath (excluding '.' and '..').
      filenames is a list of the names of the non-directory files in dirpath.
      Note that the names in the lists are just names, with no path components.
      To get a full path (which begins with top) to a file or directory in
      dirpath, do os.path.join(dirpath, name).
  
      If optional arg 'topdown' is true or not specified, the triple for a
      directory is generated before the triples for any of its subdirectories
      (directories are generated top down).  If topdown is false, the triple
      for a directory is generated after the triples for all of its
      subdirectories (directories are generated bottom up).
  
      When topdown is true, the caller can modify the dirnames list in-place
      (e.g., via del or slice assignment), and walk will only recurse into the
      subdirectories whose names remain in dirnames; this can be used to prune
      the search, or to impose a specific order of visiting.  Modifying
      dirnames when topdown is false is ineffective, since the directories in
      dirnames have already been generated by the time dirnames itself is
      generated.
  
      By default errors from the os.listdir() call are ignored.  If
      optional arg 'onerror' is specified, it should be a function; it
      will be called with one argument, an os.error instance.  It can
      report the error to continue with the walk, or raise the exception
      to abort the walk.  Note that the filename is available as the
      filename attribute of the exception object.
  
      By default, os.walk does not follow symbolic links to subdirectories on
      systems that support them.  In order to get this functionality, set the
      optional argument 'followlinks' to true.
  
      Caution:  if you pass a relative pathname for top, don't change the
      current working directory between resumptions of walk.  walk never
      changes the current directory, and assumes that the client doesn't
      either.
  
      Example:
  
      import os
      from os.path import join, getsize
      for root, dirs, files in os.walk('python/Lib/email'):
          print root, "consumes",
          print sum([getsize(join(root, name)) for name in files]),
          print "bytes in", len(files), "non-directory files"
          if 'CVS' in dirs:
              dirs.remove('CVS')  # don't visit CVS directories
      """
  
      islink, join, isdir = path.islink, path.join, path.isdir
  
      # We may not have read permission for top, in which case we can't
      # get a list of the files the directory contains.  os.path.walk
      # always suppressed the exception then, rather than blow up for a
      # minor reason when (say) a thousand readable directories are still
      # left to visit.  That logic is copied here.
      try:
          # Note that listdir and error are globals in this module due
          # to earlier import-*.
          names = listdir(top)
      except error, err:
          if onerror is not None:
              onerror(err)
          return
  
      dirs, nondirs = [], []
      for name in names:
          if isdir(join(top, name)):
              dirs.append(name)
          else:
              nondirs.append(name)
  
      if topdown:
          yield top, dirs, nondirs
      for name in dirs:
          new_path = join(top, name)
          if followlinks or not islink(new_path):
              for x in walk(new_path, topdown, onerror, followlinks):
                  yield x
      if not topdown:
          yield top, dirs, nondirs
function_tokens: def walk ( top , topdown = True , onerror = None , followlinks = False ) : islink , join , isdir = path . islink , path . join , path . isdir # We may not have read permission for top, in which case we can't # get a list of the files the directory contains.  os.path.walk # always suppressed the exception then, rather than blow up for a # minor reason when (say) a thousand readable directories are still # left to visit.  That logic is copied here. try : # Note that listdir and error are globals in this module due # to earlier import-*. names = listdir ( top ) except error , err : if onerror is not None : onerror ( err ) return dirs , nondirs = [ ] , [ ] for name in names : if isdir ( join ( top , name ) ) : dirs . append ( name ) else : nondirs . append ( name ) if topdown : yield top , dirs , nondirs for name in dirs : new_path = join ( top , name ) if followlinks or not islink ( new_path ) : for x in walk ( new_path , topdown , onerror , followlinks ) : yield x if not topdown : yield top , dirs , nondirs