__init__.py in Python

In Python, there are two types of packages named regular packages and namespace packages. The Regular packages exist in Python 3.2 and previous versions. These packages are used as a directory that contains the __init__.py file, which is implicitly called or executed.

The __init__.py file in Python lets the Interpreter knows that a directory contains a Python code in the module. This file can have the same code as any other Python module.

Files named as __init__.py are used to flag directories as Python packages.

For example,

mydir / spam / __init__.py
mydir / spam / module.py

If this file is removed, Python can not search for submodules in the directory, leading to failure in importing the module.

Main Reasons to Use __init__.py in Python

1. Using __init__.py will allow other users not to know the exact locations of the functions in the package.

your_package/
  __init__.py
  file1.py
  file2.py
    ...
  fileN.py

2. Using __init__.py will help in initializing some details like logging at the top.

import logging.config

logging.config.dictConfig(Your_logging_config)

3. __init__.py helps in easing the import of files. A function fn() can be imported from a file filename.py when it is in a package.

from filename import fn()