Import libraries from ROOT directory in python

Question

I have the following structure of my program:

MainDir
├── __init__.py
├── main.py
├── Routine.py
└── Folder1
 ├── __init__.py
 └──function.py

I know that I can import a function from folder 1 to my main.py program writing this statement:

from Folder1.function import foo

But, I am looking for a way to do so in the other direction. How could I import a function defined in Routine.py to function.py?

• paltaa: Does this answer your question? stackoverflow.com/questions/15109548/…
• paltaa: Also this: docs.python.org/2/whatsnew/…
• Erincon: The first one worked for me. I imported os library to get my current working directory and then appended it to the sys.path
• sahasrara62: in folder1/fucntion you can write from main.routine import function1

Answer 1

It depends on how you are invoking your program.

Invoking as a module

Do you do something like

python -m MainDir.main

and whatever code is in your MainDir.main calls out to MainDir/Folder1/function.py?

In this case, you can simply add the following import to MainDir/Folder1/function.py:

from ..Routine import RoutineFunction

Invoking as a script

If you are instead invoking MainDir/Folder1/function.py as a script using:

python MainDir/Folder1/function.py

you will not be able to use relative imports as suggested above. There are still many options available to you, as described here: How to import other Python files?

Suggested reading

Python imports can be very confusing. Here is a great post on the topic, which could be useful to you: https://stackoverflow.com/a/14132912/4905625