Import a file from a subdirectory?

• 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)

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.

You can try inserting it in sys.path:

sys.path.insert(0, './lib')
import BoxTime