Relative paths in Python

Question

I\'m building a simple helper script for work that will copy a couple of template files in our code base to the current directory. I don\'t, however, have the absolute path

Answer 1

From what suggest others and from pathlib documentation, a simple and clear solution is the following (suppose the file we need to refer to: Test/data/users.csv:

# This file location: Tests/src/long/module/subdir/some_script.py
from pathlib import Path

# back to Tests/
PROJECT_ROOT = Path(__file__).parents[4]
# then down to Test/data/users.csv
CSV_USERS_PATH = PROJECT_ROOT / 'data' / 'users.csv'  

with CSV_USERS_PATH.open() as users:
    print(users.read())

Now this looks a bit odd to me, because if you move some_script.py around, the path to the root of our project may change (we would need to modify parents[4]). On the other hand I found a solution that I prefer based on the same idea.

Suppose we have the following directory structure:

Tests
├── data
│  └── users.csv
└── src
   ├── long
   │  └── module
   │     └── subdir
   │        └── some_script.py
   ├── main.py
   └── paths.py

The paths.py file will be responsible for storing the root location of our projet:

from pathlib import Path

PROJECT_ROOT = Path(__file__).parents[1]

All scripts can now use paths.PROJECT_ROOT to express absolute paths from the root of the project. For example in src/long/module/subdir/some_script.py we could have:

from paths import PROJECT_ROOT

CSV_USERS_PATH = PROJECT_ROOT / 'data' / 'users.csv'

def hello():
    with CSV_USERS_PATH.open() as f:
        print(f.read())

And everything goes as expected:

~/Tests/src/$ python main.py

/Users/cglacet/Tests/data/users.csv
hello, user

~/Tests/$ python src/main.py

/Users/cglacet/Tests/data/users.csv
hello, user

The main.py script simply is:

from long.module.subdir import some_script

some_script.hello()