uos.stat(): differentiate between file and folder

[jcf]

I have not found any possibility to differentiate between file and folder, like os.path.isdir() does.
My idea is to use uos.stat()
However there is not much documentation.
So I tried this:

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>>> import uos
>>> uos.stat('SD')						# this is a folder
(16384, 0, 0, 0, 0, 0, 536892856, 0, 0, 0)
>>> uos.stat('filetools.py')				# this is a file
(32768, 0, 0, 0, 0, 0, 1507, 1609470216, 1609470216, 1609470216)

Can I use the difference in the first return value to make the difference? Does that always work?

[Roberthh]

The answer to your question is yes. 32768 tells, that it is a file.

[dhylands]

Note that the value is actually a collection of bit fields, so to check properly you should just be checking for a particular bit value.

So for example:

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val = uos.stat(filename)
if val[0] & 0x4000 != 0:
    print('This is a directory')
if val[0] & 0x8000 != 0:
    print('This is a file')

[jcf]

That's exactly what I thought.
So I wrote these short functions that seem to work fine:

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def is_folder(filename):
    if uos.stat(filename)[0] & 0x4000:
        return True
    else:
        return False
    
def list_folders(folder):
    # list subfolders of folder
    l = uos.listdir(folder)
    folders = [f for f in l if is_folder(f)]
    return folders

Is there any official documentation on the stat function?

[hippy]

Is there any official documentation on the stat function?

Not a lot that I found. Just "Get the status of a file or directory" at https://docs.micropython.org/en/latest/library/uos.html

My go to reference is an earlier post by Roberthh - viewtopic.php?t=5291

Given the RP2 has a reasonable amount of Flash I believe there is a case which can be made to add os.path.isfile() etc for that port. This would really help Python programmers coming from Pi to migrate to MicroPython.

[dhylands]

The values 0x8000 and 0x4000 correspond to the values stat.IFREG and stat.IFDIR from CPython:

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Python 3.7.4 (default, Aug 13 2019, 15:17:50) 
[Clang 4.0.1 (tags/RELEASE_401/final)] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import stat
>>> hex(stat.S_IFREG)
'0x8000'
>>> hex(stat.S_IFDIR)
'0x4000'
>>> 

This page: https://docs.python.org/3/library/stat.html has the documentation for the return values from os.stat() used by CPython.
https://docs.python.org/3/library/stat.html

For the FAT filesystem, S_IFREG and S_IFDIR are the only two flags that would ever be non-zero (st_mode also includes the user/group/other permissions, so read-only files might get mapped in there somehow).