Reading file using relative path in python project

Say I have a python project that is structured as follows:

    project
        /data
            test.csv
        /package
            __init__.py
            module.py
        main.py

__init__.py:

    from .module import test

module.py:

    import csv

    with open("..data/test.csv") as f:
        test = [line for line in csv.reader(f)]

main.py:

    import package

    print(package.test)

When I run main.py I get the following error:

     C:\Users\Patrick\Desktop\project>python main.py
    Traceback (most recent call last):
      File "main.py", line 1, in <module>
        import package
      File "C:\Users\Patrick\Desktop\project\package\__init__.py", line 1, in <module>
        from .module import test
      File "C:\Users\Patrick\Desktop\project\package\module.py", line 3, in <module>
        with open("../data/test.csv") as f:
    FileNotFoundError: [Errno 2] No such file or directory: '../data/test.csv'

However, if I run module.py from the package directory I get no errors. So it seems that the relative path used in open(...) is only relative to where the originating file is being run from (i.e __name__ == "__main__")? I don't want to use absolute paths. What are some ways to deal with this?

Relative paths are relative to current working directory. If you do not your want your path to be, it must be absolute.

But there is an often used trick to build an absolute path from current script: use its __file__ special attribute:

    import csv
    import os.path

    my_path = os.path.abspath(os.path.dirname(__file__))
    path = os.path.join(my_path, "../data/test.csv")
    with open(path) as f:
        test = list(csv.reader(f))

Note, from python 3.4, __file__ is always absolute for imported modules and you can drop the os.path.abspath part in this example.

Better yet with python 3.4+, use the Path module as jpyams suggested in the comment below:

    from pathlib import Path

    path = Path(__file__).parent / "../data/test.csv"
    with path.open() as f:
        test = list(csv.reader(f))

From: stackoverflow.com/q/40416072