How to Create a Python Package

When you’ve got a large number of Python classes (or “modules”), you’ll want to organize them into packages. When the number of modules (simply stated, a module might be just a file containing some classes) in any project grows significantly, it is wiser to organize them into packages – that is, placing functionally similar modules/classes in the same directory. This article will show you how to create a Python package.

Steps to Create a Python Package

Working with Python packages is really simple. All you need to do is:

1. Create a directory and give it your package’s name.
2. Put your classes in it.
3. Create a __init__.py file in the directory

That’s all! In order to create a Python package, it is very easy. The __init__.py file is necessary because with this file, Python will know that this directory is a Python package directory other than an ordinary directory (or folder – whatever you want to call it). Anyway, it is in this file where we’ll write some import statements to import classes from our brand new package.

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Example On How to Create a Python Package

In this tutorial, we will create an Animals package – which simply contains two module files named Mammals and Birds, containing the Mammals and Birds classes, respectively.

Step 1: Create the Package Directory

So, first we create a directory named Animals.

Step 2: Add Classes

Now, we create the two classes for our package. First, create a file named Mammals.py inside the Animals directory and put the following code in it:

class Mammals:
    def __init__(self):
        ''' Constructor for this class. '''
        # Create some member animals
        self.members = ['Tiger', 'Elephant', 'Wild Cat']
 
 
    def printMembers(self):
        print('Printing members of the Mammals class')
        for member in self.members:
            print('\t%s ' % member)

The code is pretty much self-explanatory! The class has a property named members – which is a list of some mammals we might be interested in. It also has a method named printMembers which simply prints the list of mammals of this class! Remember, when you create a Python package, all classes must be capable of being imported, and won’t be executed directly.

Next we create another class named Birds. Create a file named Birds.py inside the Animals directory and put the following code in it:

class Birds:
    def __init__(self):
        ''' Constructor for this class. '''
        # Create some member animals
        self.members = ['Sparrow', 'Robin', 'Duck']
 
 
    def printMembers(self):
        print('Printing members of the Birds class')
        for member in self.members:
           print('\t%s ' % member)

This code is similar to the code we presented for the Mammals class.

Step 3: Add the __init__.py File

Finally, we create a file named __init__.py inside the Animals directory and put the following code in it:

from Mammals import Mammals
from Birds import Birds

That’s it! That’s all there is to it when you create a Python package. For testing, we create a simple file named test.py in the same directory where the Animals directory is located. We place the following code in the test.py file:

# Import classes from your brand new package
from Animals import Mammals
from Animals import Birds
 
# Create an object of Mammals class & call a method of it
myMammal = Mammals()
myMammal.printMembers()
 
# Create an object of Birds class & call a method of it
myBird = Birds()
myBird.printMembers()