Import a module from a relative path

Question

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 1

Be sure that dirBar has the __init__.py file -- this makes a directory into a Python package.

Answer 2

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 the 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. It probably fails too.