Python – Creating and Installing a Package

Created with Sketch.

Python – Creating and Installing a Package

We organize a large number of files in different folders and subfolders based on some criteria, so that we can find and manage them easily.
In the same way, a package in Python takes the concept of the modular approach to next logical level.
As you know, a module can contain multiple objects, such as classes, functions, etc.
A package can contain one or more relevant modules. Physically, a package is actually a folder containing one or more module files.

Let’s create a package named mypackage, using the following steps:

  • Create a new folder named D:\MyApp.
  • Inside MyApp, create a subfolder with the name ‘mypackage’.
  • Create an empty file in the mypackage folder.
  • Using a Python-aware editor like IDLE, create modules and with following code:
def SayHello(name):
    print("Hello " + name)
def sum(x,y):
    return x+y

def average(x,y):
    return (x+y)/2

def power(x,y):
    return x**y


That’s it. We have created our package called mypackage. The following is a folder structure:

Package Folder Structure
Package Folder Structure

Importing a Module from a Package

Now, to test our package, invoke the Python prompt from the MyApp folder.


Import the functions module from the mypackage package and call its power() function.

>>> from mypackage import functions
>>> functions.power(3,2)

It is also possible to import specific functions from a module in the package

>>> from mypackage.functions import sum
>>> sum(10,20)
>>> average(10,12)
Traceback (most recent call last):
File “<pyshell#13>”, line 1, in <module>
NameError: name ‘average’ is not defined

The package folder contains a special file called, which stores the package’s content. It serves two purposes:

  1. The Python interpreter recognizes a folder as the package if it contains file.
  2. exposes specified resources from its modules to be imported.

An empty file makes all functions from above modules available when this package is imported. Note that is essential for the folder to be recognized by Python as a package. You can optionally define functions from individual modules to be made available.

We shall also create another Python script in the MyApp folder and import the mypackage package in it.
It should be at the same level of the package to be imported.

The file is normally kept empty. However, it can also be used to choose specific functions from modules in the package folder and make them available for import. Modify as below:
from .functions import average, power
from .greet import SayHello


The specified functions can now be imported in the interpreter session or another executable script.

Create in the MyApp folder to test mypackage.
from mypackage import power, average, SayHello
print("power(3,2) : ", x)


Note that functions power() and SayHello() are imported from the package and not from their respective modules, as done earlier. The output of above script is:

Hello world
power(3,2) : 9

Install a Package Globally

Once a package is created, it can be installed for system wide use by running the setup script. The script calls setup() function from setuptools module.

Let’s install mypackage for system-wide use by running a setup script.

Save the following code as in the parent folder ‘MyApp’. The script calls the setup() function from the setuptools module. The setup() function takes various arguments such as name, version, author, list of dependencies etc. The zip_safe argument defines whether the package is installed in compressed mode or regular mode.

from setuptools import setup
description='Testing installation of Package',


Now execute the following command to install mypack using the pip utility.
Ensure that the command prompt is in the parent folder, in this case D:\MyApp.

D:\MyApp>pip install .
Processing d:\MyApp
Installing collected packages: mypack
Running install for mypack … done
Successfully installed mypackage-0.1

Now mypackage is available for system-wide use and can be imported in any script or interpreter.

>>> import mypackage

You may also want to publish the package for public use. PyPI (stands for Python Package Index) is a repository of Python packages and is hosted at
Those interested in finding out more about the procedure of uploading a package to PyPI visit

Leave a Reply

Your email address will not be published. Required fields are marked *