I have a file called tester.py, located on /project.

/project has a subdirectory called lib, with a file called BoxTime.py:

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

I want to import BoxTime from tester. I have tried this:

import lib.BoxTime

Which resulted:

Traceback (most recent call last): File "./tester.py", line 3, in <module> import lib.BoxTime ImportError: No module named lib.BoxTime

Any ideas how to import BoxTime from the subdirectory?

EDIT

The __init__.py was the problem, but don't forget to refer to BoxTime as lib.BoxTime, or use:

import lib.BoxTime as BT ... BT.bt_function()
1

12 Answers

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.

7
  • 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!
8

You can try inserting it in sys.path:

sys.path.insert(0, './lib') import BoxTime
9

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)
3

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

4

Does your lib directory contain a __init__.py file?

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

Full example included

This basically covers all cases (make sure you have __init__.py in relative/path/to/your/lib/folder):

import sys, os sys.path.append(os.path.dirname(os.path.realpath(__file__)) + "/relative/path/to/your/lib/folder") import someFileNameWhichIsInTheFolder ... somefile.foo()

Example:

You have in your project folder: 

/root/myproject/app.py

You have in another project folder: 

/root/anotherproject/utils.py /root/anotherproject/__init__.py

You want to use /root/anotherproject/utils.py and call foo function which is in it.

So you write in app.py:

import sys, os sys.path.append(os.path.dirname(os.path.realpath(__file__)) + "/../anotherproject") import utils utils.foo()
4

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()
1

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.

2

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).

/project/tester.py

/project/lib/BoxTime.py

create blank file __init__.py down the line till you reach the file

/project/lib/somefolder/BoxTime.py

#lib -- needs has two items one __init__.py and a directory named somefolder #somefolder has two items boxtime.py and __init__.py

try this:

from lib import BoxTime

1