Python Basics: File System Operations (Summary)

nicely constructed course for beginners although it has references to generators and tuples so good to leave some supporting materials or links to read for absolute beginners to fit the title of this course. Overall it is a good course to clear the basic concepts of file system.

The supporting material is very sparse, basically only has the exercises, so not of any use. It would be better if the key slides were included for reference, as is included in most other courses. Can that be updated?

I apologise, I was looking at the pb-filesystem-exercises.pdf which I had downloaded. I did get the course slides pb-filesystem_JO2FIPC.pdf so all is ok. Many thanks.

A question on error handling when removing empty and non-empty directories. With files we saw that .unlink(missing_ok=True) covers that position. I’ve looked and cannot find a corresponding simple entry for similarly managing folders. Is there one or is the only way to check whether the path exists?

@tonypy not totally sure I understand what you’re asking, it seems that there are two concepts that you’re maybe mixing together?

1. Deleting empty and non-empty directories
2. Deleting existing empty directories, and continuing execution if a directory doesn’t exist

For the empty/non-empty directories situation, there are examples in the lessons on deleting an empty folder and deleting a non-empty folder, so I think you were wondering about point two, which also makes sense because you’re mentioning missing_ok from .unlink().

For deleting existing empty directories, you work with .rmdir(). You can see in the documentation that .rmdir() doesn’t take any arguments. If you take a look into the source code, then you can see that all the method does is calling os.rmdir() on the Path object.

The Python documentation on os.rmdir() shows that the function raises a FileNotFound error if the directory doesn’t exist, which you’ve probably seen and you can confirm in a REPL session:

>>> from pathlib import Path
>>> Path.home().joinpath("not-there").rmdir()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/martin/.pyenv/versions/3.11.0/lib/python3.11/pathlib.py", line 1156, in rmdir
    os.rmdir(self)
FileNotFoundError: [Errno 2] No such file or directory: '/Users/martin/not-there'

So, one way to manage the control flow around this situation is that you can handle that exception:

try:
    your_directory_path_object.rmdir()
except FileNotFoundError:
    pass

This try...except block essentially reproduces the functionality described in #2 above: It’ll delete existing empty directories, and continuing execution if a directory doesn’t exist.

Tl;DR: No, .rmdir() doesn’t have such an argument, but because it raises a specific exception, you can catch that exception and write code that has the same functionality as what .unlink(missing_ok=True) gives you for files, also without checking whether the path exists.

Many thanks for the feedback. In summary, there isnt a nice simple entry that can be included like “exist_ok=True”. I have therefore used the following to preclude the occurrence of the error where no directory exists:

if old_dir.exists():
    shutil.rmtree(old_dir)

@tonypy ah if you want to use shutil.rmtree() then it looks like you can use ignore_errors=True:

shutil.rmtree(old_dir, ignore_errors_True)

However, I’d advise you to be very careful with this function, because it can really delete a lot at once! It’s best to be very conservative with using it.

Thanks for the update and warning.

Before I started this course, I was a bit confused by 4 Python Packages: os, sys, pathlib and shutil. When do you need one of these packages, as for instance os and pathlib seem to overlap a lot. Now I learned a lot about pathlib, next are the other packages. It may be handy to create an additional course about Python packages: how to get your best modules pick for the task (file system related)

This course helped me a lot on the pathlib module. It carefully explains how to create, delete, and move files and folders/directories.