How to get all of the immediate subdirectories in Python

Question

I'm trying to write a simple Python script that will copy a index.tpl to index.html in all of the subdirectories (with a few exceptions). I'm getting bogged down by trying to get the list of subdirectories.

Accepted Answer

I did some speed testing on various functions to return the full path to all current subdirectories.

tl;dr: Always use `scandir`:

`list_subfolders_with_paths = [f.path for f in os.scandir(path) if f.is_dir()]`

Bonus: With `scandir` you can also simply only get folder names by using `f.name` instead of `f.path`.

This (as well as all other functions below) will not use natural sorting. This means results will be sorted like this: 1, 10, 2. To get natural sorting (1, 2, 10), please have a look at https://stackoverflow.com/a/48030307/2441026

Results: `scandir` is: 3x faster than `walk`, 32x faster than `listdir` (with filter), 35x faster than `Pathlib` and 36x faster than `listdir` and 37x (!) faster than `glob`.

```
Scandir:           0.977
Walk:              3.011
Listdir (filter): 31.288
Pathlib:          34.075
Listdir:          35.501
Glob:             36.277
```

Tested with W7x64, Python 3.8.1. Folder with 440 subfolders. In case you wonder if `listdir` could be speed up by not doing os.path.join() twice, yes, but the difference is basically nonexistent.

Code:

```
import os
import pathlib
import timeit
import glob

path = r"<example_path>"

def a():
    list_subfolders_with_paths = [f.path for f in os.scandir(path) if f.is_dir()]
    # print(len(list_subfolders_with_paths))

def b():
    list_subfolders_with_paths = [os.path.join(path, f) for f in os.listdir(path) if os.path.isdir(os.path.join(path, f))]
    # print(len(list_subfolders_with_paths))

def c():
    list_subfolders_with_paths = []
    for root, dirs, files in os.walk(path):
        for dir in dirs:
            list_subfolders_with_paths.append( os.path.join(root, dir) )
        break
    # print(len(list_subfolders_with_paths))

def d():
    list_subfolders_with_paths = glob.glob(path + '/*/')
    # print(len(list_subfolders_with_paths))

def e():
    list_subfolders_with_paths = list(filter(os.path.isdir, [os.path.join(path, f) for f in os.listdir(path)]))
    # print(len(list(list_subfolders_with_paths)))

def f():
    p = pathlib.Path(path)
    list_subfolders_with_paths = [x for x in p.iterdir() if x.is_dir()]
    # print(len(list_subfolders_with_paths))

print(f"Scandir:          {timeit.timeit(a, number=1000):.3f}")
print(f"Listdir:          {timeit.timeit(b, number=1000):.3f}")
print(f"Walk:             {timeit.timeit(c, number=1000):.3f}")
print(f"Glob:             {timeit.timeit(d, number=1000):.3f}")
print(f"Listdir (filter): {timeit.timeit(e, number=1000):.3f}")
print(f"Pathlib:          {timeit.timeit(f, number=1000):.3f}")
```

How to get all of the immediate subdirectories in Python

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