Python Language makedirs - recursive directory creation


Example

Given a local directory with the following contents:

 └── dir1
     ├── subdir1
     └── subdir2

We want to create the same subdir1, subdir2 under a new directory dir2, which does not exist yet.

import os

os.makedirs("./dir2/subdir1")
os.makedirs("./dir2/subdir2")

Running this results in

├── dir1
│   ├── subdir1
│   └── subdir2
└── dir2
    ├── subdir1
    └── subdir2

dir2 is only created the first time it is needed, for subdir1's creation.

If we had used os.mkdir instead, we would have had an exception because dir2 would not have existed yet.

    os.mkdir("./dir2/subdir1")
OSError: [Errno 2] No such file or directory: './dir2/subdir1'

os.makedirs won't like it if the target directory exists already. If we re-run it again:

OSError: [Errno 17] File exists: './dir2/subdir1'

However, this could easily be fixed by catching the exception and checking that the directory has been created.

try:
    os.makedirs("./dir2/subdir1")
except OSError:
    if not os.path.isdir("./dir2/subdir1"):
        raise

try:
    os.makedirs("./dir2/subdir2")
except OSError:
    if not os.path.isdir("./dir2/subdir2"):
        raise