init.py : It is a python file found in a package directory, it is invoked when the package or a module in the package is imported. You can use this to execute package initialization code, i.e. whenever the package is imported the python statements are executed first before the other modules in this folder gets executed. It is similar to main function of c or java program but this exists in the python package module(folder) rather than in the core python file. also it has access to global variables defined in this init.py file as when the module is imported into python file.

for eg. I have a init.py file in a folder called pymodlib, this file contains the following statements:

print(f'Invoking init.py for {name}') pystructures = ['for_loop', 'while__loop', 'ifCondition']

when I import this package "pymodlib" in the my solution module or notebook or python console: this two statements gets executed while importing. So in the log or console you would see the following output:

import pymodlib Invoking init.py for pymodlib

in the next statement of python console: I can access the global variable:

pymodlib.pystructures it gives the following output:

['for_loop', 'while__loop', 'ifCondition']

Now from python3.3 onwards the use of this file has been optional to make folder a python module. So you skip from including it in the python module folder.

__init__.py : It is a Python file found in a package directory, it is invoked when the package or a module in the package is imported. You can use this to execute package initialization code, i.e. whenever the package is imported the python statements are executed first before the other modules in this folder gets executed. It is similar to main function of c or Java program, but this exists in the Python package module  (folder) rather than in the core Python file. also it has access to global variables defined in this __init__.py file as when the module is imported into Python file.

for eg. 
I have a __init__.py file in a folder called pymodlib, this file contains the following statements:

print(f'Invoking __init__.py for {__name__}')
pystructures = ['for_loop', 'while__loop', 'ifCondition']

When I import this package pymodlib in my solution module or notebook or python console: 
These two statements get executed while importing. So in the log or console you would see the following output:

>>> import pymodlib
Invoking __init__.py for pymodlib

in the next statement of python console: I can access the global variable:

>> pymodlib.pystructures

it gives the following output:

['for_loop', 'while__loop', 'ifCondition']

Now, from Python 3.3 onwards the use of this file has been optional to make folder a Python module. So you can skip from including it in the python module folder.