Import a file from a subdirectory?

Take a look at the Packages documentation (Section 6.4).

In short, you need to put a blank file named

__init__.py

in the lib directory.

• Create a subdirectory named lib.
• Create an empty file named lib\__init__.py.

• In lib\BoxTime.py, write a function foo() like this:

  def foo():
      print "foo!"
  

• In your client code in the directory above lib, write:

  from lib import BoxTime
  BoxTime.foo()
  

• Run your client code. You will get:

  foo!
  

Much later -- in linux, it would look like this:

% cd ~/tmp
% mkdir lib
% touch lib/__init__.py
% cat > lib/BoxTime.py << EOF
heredoc> def foo():
heredoc>     print "foo!"
heredoc> EOF
% tree lib
lib
├── BoxTime.py
└── __init__.py

0 directories, 2 files
% python 
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from lib import BoxTime
>>> BoxTime.foo()
foo!

I am writing this down because everyone seems to suggest that you have to create a lib directory.

You don't need to name your sub-directory lib. You can name it anything provided you put an __init__.py into it.

You can do that by entering the following command in a linux shell:

$ touch anything/__init__.py 

So now you have this structure:

$ ls anything/
__init__.py
mylib.py

$ ls
main.py

Then you can import mylib into main.py like this:

from anything import mylib 

mylib.myfun()

You can also import functions and classes like this:

from anything.mylib import MyClass
from anything.mylib import myfun

instance = MyClass()
result = myfun()

Any variable function or class you place inside __init__.py can also be accessed:

import anything

print(anything.myvar)

Or like this:

from anything import myvar

print(myvar)

Try import .lib.BoxTime. For more information read about relative import in PEP 328.

Does your lib directory contain a __init__.py file?

Python uses __init__.py to determine if a directory is a module.

Create an empty file __init__.py in subdirectory /lib. And add at the begin of main code

from __future__ import absolute_import 

then

import lib.BoxTime as BT
...
BT.bt_function()

or better

from lib.BoxTime import bt_function
...
bt_function()

Just an addition to these answers.

If you want to import all files from all subdirectories, you can add this to the root of your file.

import sys, os
sys.path.extend([f'./{name}' for name in os.listdir(".") if os.path.isdir(name)])

And then you can simply import files from the subdirectories just as if these files are inside the current directory.

Working example

If I have the following directory with subdirectories in my project...

.
├── a.py
├── b.py
├── c.py
├── subdirectory_a
│   ├── d.py
│   └── e.py
├── subdirectory_b
│   └── f.py
├── subdirectory_c
│   └── g.py
└── subdirectory_d
    └── h.py

I can put the following code inside my a.py file

import sys, os
sys.path.extend([f'./{name}' for name in os.listdir(".") if os.path.isdir(name)])

# And then you can import files just as if these files are inside the current directory

import b
import c
import d
import e
import f
import g
import h

In other words, this code will abstract from which directory the file is coming from.

For this folder hierarchy diagram example:

/project/tester.py    
/project/lib/BoxTime.py

1- Create a blank py file __init__.py inside lib folder

2- In the caller py file tester.py add theses code lines

import os, sys
sys.path.insert(0,'lib')# insert the folder lib in system path
from BoxTime import Function_name # from the py file import the needed function

Easy explanation can be found in here.

Notice: This is refered to as creating/importing modules in/from different folder.

Personel experience: I tried to create module from jupyter notebook, it did not not work (maybe I done it improperly using .ipynb), I needed to do it manually outside the juypyter notebook, or using other IDE (e.g. pycharm).

create_card.py

 init():
   print('Hello world!')

app.py

import create_card

create_card.init()

if you want to import only required functions

from create_card import init

If you have nested directories (Ex: modules/aadhaar/create-card.py)

import modules.aadhaar.create_card as create_card or from modules.aadhaar.create_card import init