[FIXED] Python 2.7 cannot find module in its search path

Issue

I wanted to test the relative import model of Python 2.X

Directory tree:

exercises/
    dir1/
        dir2/
            mod.py
            dir3/
                mod2.py
                mod3.py

mod.py

import sys
print 'in dir1/dir2/mod.py'
path = [name for name in sys.path if 'Frameworks' not in name]. 
print 'Module search path of mod is:\n' + str(path)

import dir3.mod2

mod2.py

print 'in dir1/dir2/dir3/mod2.py' 
import mod3

mod3.py

print 'in dir1/dir2/dir3/mod3.py by relative import'

'mod' would import 'mod2' from 'dir3', which would then import 'mod3'. In Python 3.X, this would fail because the path to 'mod3' is not provided; in Python 2.X, the interpreter searches the same directory containing 'mod2' before searching the rest of the path starting from the top level directory of 'mod'.

This is the error message I get:

MacBook-Pro-9 exercises % python dir1/dir2/mod.py
in dir1/dir2/mod.py
Module search path of mod is:
['Users/arthur/Desktop/learning_python/exercises/dir1/dir2', '/Library/Python/2.7/site-packages']
Traceback (most recent call last):
  File "Desktop/learning_python/exercises/dir1/dir2/mod.py", line 8, in <module>
    import dir3.mod2
ImportError: No module named dir3.mod2

I know 'dir2' contains 'dir3/mod2', but for some reason, Python can't find it. I'm pretty sure that the syntax for the import statement is correct.

I modified the print statements and changed 'mod2.py' code to read from . import mod3. I edited nothing else, and it ran just fine in Python 3.8 There was no problem finding 'dir3.mod2'

Solution

You have to add an empty file inside dir3 named init.py for python to be able to recognize the directory as a Python package directory. If you have these files

dir3/__init__.py
dir3/mod2.py
dir3/mod3.py

You can now import the code in mod2.py and mod3.py as

import dir3.mod2
import dir3.mod3

or

from dir3 import mod2
from dir3 import mod3

If you remove the init.py file, Python will no longer look for submodules inside that directory, so attempts to import the module will fail.

Here is the a link.

Answered By - lirivera