Python Reliable Path to File

Using pathlib

from pathlib import Path

__location__ = Path(__file__).parent.resolve()

As an example, we could read a file my_file.json located at the same folder as the python script.

with open(os.path.join(__location__, 'my_file.json'), 'r') as f:
    data_from_file = json.loads( f.read() )

Playground

Using os

Python os module provides several useful functions too. This is NOT recommended anymore. But if one insists, we can easily make it work.

The following code will determine the path to the file.

__location__ = os.path.realpath(
  os.path.join(
    os.getcwd(),
    os.path.dirname(os.path.abspath(__file__))
  )
)

For the same example as above, we could read a file my_file.json located at the same folder as the python script.

with open(os.path.join(__location__, 'my_file.json'), 'r') as f:
    data_from_file = json.loads( f.read() )

We can understand how it works by breaking it down.

1. os.getcwd(): get current working directory. Current working directory is defined as where the python script is executed.

   ➜  Downloads python temp.py
   os.getcwd:  /Users/datumorphism/Downloads
   ➜  ~ python Downloads/temp.py
   os.getcwd:  /Users/datumorphism
   

2. __file__: is basically the file name. Suppose we have a python script with name main.py.

   print('__file__: ', __file__)
   

   will return __file__: main.py.

3. os.path.abspath retrieves the absolute path of the file.

   file_absolute_path = os.path.abspath(__file__)
   

4. os.path.join joins the strings into path, intelligently.

   print('os.path.join("datumorphism", "main.py"): ', os.path.join("datumorphism", "main.py") )
   

   will return os.path.join("datumorphism", "main.py"): datumorphism/main.py.

Playground