python – Import a file from a subdirectory?

The Question :

499 people think this question is useful

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()

The Question Comments :

The Answer 1

572 people think this answer is useful

Take a look at the Packages documentation (Section 6.4) here: http://docs.python.org/tutorial/modules.html

In short, you need to put a blank file named

__init__.py

in the “lib” directory.

The Answer 2

189 people think this answer is useful
  • 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!

The Answer 3

73 people think this answer is useful

You can try inserting it in sys.path:

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

The Answer 4

37 people think this answer is useful

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)

The Answer 5

21 people think this answer is useful

Does your lib directory contain a __init__.py file?

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

The Answer 6

17 people think this answer is useful

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

The Answer 7

11 people think this answer is useful

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()

The Answer 8

6 people think this answer is useful

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()

The Answer 9

4 people think this answer is useful

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.

The Answer 10

-1 people think this answer is useful

/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

The Answer 11

-3 people think this answer is useful

try this:

from lib import BoxTime

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