Jude Allred Jude Allred - 4 months ago 25
Python Question

Import a module from a relative path

How do I import a python module given its relative path?

For example, if

dirFoo
contains
Foo.py
and
dirBar
, and
dirBar
contains
Bar.py
, how do I import
Bar.py
into
Foo.py
?

Here's a visual representation:

dirFoo\
Foo.py
dirBar\
Bar.py


Foo
wishes to include
Bar
, but restructuring the folder hierarchy is not an option.

Answer

Assuming that both your directories are real python packages (do have the __init__.py file inside them), here is a safe solution for inclusion of modules relatively to the location of the script.

I assume that you want to do this because you need to include a set of modules with your script. I use this in production in several products and works in many special scenarios like: scripts called from another directory or executed with python execute instead of opening a new interpreter.

 import os, sys, inspect
 # realpath() will make your script run, even if you symlink it :)
 cmd_folder = os.path.realpath(os.path.abspath(os.path.split(inspect.getfile( inspect.currentframe() ))[0]))
 if cmd_folder not in sys.path:
     sys.path.insert(0, cmd_folder)

 # use this if you want to include modules from a subfolder
 cmd_subfolder = os.path.realpath(os.path.abspath(os.path.join(os.path.split(inspect.getfile( inspect.currentframe() ))[0],"subfolder")))
 if cmd_subfolder not in sys.path:
     sys.path.insert(0, cmd_subfolder)

 # Info:
 # cmd_folder = os.path.dirname(os.path.abspath(__file__)) # DO NOT USE __file__ !!!
 # __file__ fails if script is called in different ways on Windows
 # __file__ fails if someone does os.chdir() before
 # sys.argv[0] also fails because it doesn't not always contains the path

As a bonus, this approach does let you force Python to use your module instead of the ones installed on the system.

Warning! I don't really know what is happening when current module is inside an egg file. Probably it fails too. Add a comment if you really need a better solution, I may invest few more hours in improving it.