Example 4-4. PP4E\System\Filetools\lister_walk.py
"list file tree with os.walk"
import sys, os
def lister(root): # for a root dir
for (thisdir, subshere, fileshere) in os.walk(root): # generate dirs in tree
print('[' + thisdir + ']')
for fname in fileshere: # print files in this dir
path = os.path.join(thisdir, fname) # add dir name prefix
print(path)
if name == 'main':
lister(sys.argv[1]) # dir name in cmdline
When packaged this way, the code can also be run from a shell command line. Here it
is being launched with the root directory to be listed passed in as a command-line
argument:
C:\...\PP4E\System\Filetools> python lister_walk.py C:\temp\test
[C:\temp\test]
C:\temp\test\random.bin
C:\temp\test\spam.txt
C:\temp\test\temp.bin
C:\temp\test\temp.txt
[C:\temp\test\parts]
C:\temp\test\parts\part0001
C:\temp\test\parts\part0002
C:\temp\test\parts\part0003
C:\temp\test\parts\part0004Here’s a more involved example of os.walk in action. Suppose you have a directory tree
of files and you want to find all Python source files within it that reference the mime
types module we’ll study in Chapter 6. The following is one (albeit hardcoded and
overly specific) way to accomplish this task:
>>> import os
>>> matches = []
>>> for (dirname, dirshere, fileshere) in os.walk(r'C:\temp\PP3E\Examples'):
... for filename in fileshere:
... if filename.endswith('.py'):
... pathname = os.path.join(dirname, filename)
... if 'mimetypes' in open(pathname).read():
... matches.append(pathname)
...
>>> for name in matches: print(name)
...
C:\temp\PP3E\Examples\PP3E\Internet\Email\mailtools\mailParser.py
C:\temp\PP3E\Examples\PP3E\Internet\Email\mailtools\mailSender.py
C:\temp\PP3E\Examples\PP3E\Internet\Ftp\mirror\downloadflat.py
C:\temp\PP3E\Examples\PP3E\Internet\Ftp\mirror\downloadflat_modular.py
C:\temp\PP3E\Examples\PP3E\Internet\Ftp\mirror\ftptools.py
C:\temp\PP3E\Examples\PP3E\Internet\Ftp\mirror\uploadflat.py
C:\temp\PP3E\Examples\PP3E\System\Media\playfile.py170 | Chapter 4: File and Directory Tools