[Python] Singleton

Multiple ways :

• Way 1

class MyClass:
  def __init__(self):
    pass


  @classmethod
  def get(cls):
    try:
      return cls.instance
    except AttributeError:
      cls.instance = MyClass()
      return cls.instance

• Way 2

import sys

this = sys.modules[__name__]

class MyClass:
  def __init__(self):
    pass

def get_my_singleton():
  try:
    return this.my_singleton
  except AttributeError:
    this.my_singleton = MyClass()
    return this.my_singleton
More details about this way: https://stackoverflow.com/a/35904211

[Python] Difference between package and module

A module is a file :-) Modules are used to keep logically related code functions/classes together.


A package is a folder containing a set of modules.

A package may contain sub-packages.

A package must have a __init__.py at the root of the directory. When a package is imported, this __init__.py file is implicitly executed. https://docs.python.org/3/reference/import.html#regular-packages

Packaging help you to keep logically related set of modules together just as modules are used to keep logically related code functions/classes together.

With Python 3.3 and later, a package is called a regular package, and a new type of package appears : namspace package. https://docs.python.org/3/reference/import.html#namespace-packages