How to refer to relative paths of resources when working with a code repository in Python


Question

We are working with a code repository which is deployed both to Windows and Linux - sometimes on different directories. How should one of the modules inside the project refer to one of the non-Python resources in the project (CSV files, etc.)?

If we do something like:

thefile=open('test.csv')

or:

thefile=open('../somedirectory/test.csv')

It will work only when the script is run from one specific directory, or a subset of the directories.

What I would like to do is something like:

path=getBasePathOfProject()+'/somedirectory/test.csv'
thefile=open(path)

Is this the right way? Is it possible?

1
171
5/23/2017 8:41:51 PM

Accepted Answer

Try to use a filename relative to the current files path. Example for './my_file':

fn = os.path.join(os.path.dirname(__file__), 'my_file')

In Python 3.4+ you can also use pathlib:

fn = pathlib.Path(__file__).parent / 'my_file'
229
7/2/2019 3:17:29 PM

If you are using setup tools or distribute (a setup.py install) then the "right" way to access these packaged resources seem to be using package_resources.

In your case the example would be

import pkg_resources
my_data = pkg_resources.resource_string(__name__, "foo.dat")

Which of course reads the resource and the read binary data would be the value of my_data

If you just need the filename you could also use

resource_filename(package_or_requirement, resource_name)

Example:

resource_filename("MyPackage","foo.dat")

The advantage is that its guaranteed to work even if it is an archive distribution like an egg.

See http://packages.python.org/distribute/pkg_resources.html#resourcemanager-api


Licensed under: CC-BY-SA with attribution
Not affiliated with: Stack Overflow
Icon