What is a Python Module

Summary: in this tutorial, you’ll learn about what a python module is and understand how it works.

What is a python module #

So far, you learned that a module in Python is a file that contains Python code. In fact, everything in Python is an object, including a module.

When you import a module using the import statement, Python creates a new module object. For example, the following imports the math built-in module:

import math

Python creates a new variable called math that references a module object:

import math

print(math)

The math is a variable that references a module object:

<module 'math' (built-in)>

The module name is math. The type of the math module is the class module:

<class 'module'>

If you look at the globals(), you’ll see the math variable in the global namespace:

import math
from pprint import pprint

pprint(globals())

Output:

{'__annotations__': {},
 '__builtins__': <module 'builtins' (built-in)>,
 '__doc__': None,
 '__loader__': <class '_frozen_importlib.BuiltinImporter'>,
 '__name__': '__main__',
 '__package__': None,
 '__spec__': None,
 'math': <module 'math' (built-in)>,
 'pprint': <function pprint at 0x0000023FE66491F0>}

Since math is an object, you can access its attributes. For example, you can get the name of the math object using the __name__ attribute:

import math

print(math.__name__)

Output:

math

And you can access all of the attributes of the math object via the __dict__ :

import math
from pprint import pprint

pprint(math.__dict__)

Output:

'__doc__': 'This module provides access to the mathematical functions\n'
            'defined by the C standard.',
 '__loader__': <class '_frozen_importlib.BuiltinImporter'>,
 '__name__': 'math',
 '__package__': '',
 '__spec__': ModuleSpec(name='math', loader=<class '_frozen_importlib.BuiltinImporter'>, origin='built-in'),
 'acos': <built-in function acos>,

 ...

And you can use math as a regular variable. For example, you can set it to None:

math = None

This instructs Python to destroy the module object that the math variable references.

The math is an instance of the ModuleType:

import math
from types import ModuleType

pprint(isinstance(math,ModuleType))

Output:

True

The math module is a built-in module. Let’s examine a non-built-in module.

Non-built-in module #

The abc module allows you to define abstract base classes. It is not a built-in module:

import abc

print(abc)

Output:

<module 'abc' from 'C:\\Python\\lib\\abc.py'>

The abc module is defined in lib\abc.py file in Python’s installation folder. Unlike the math module which is a built-in module.

The type of the abc is also module:

import abc

print(type(abc))

Output:

<class 'module'>

Like the math module, the abc is an instance of the ModuleType as shown in the following example:

import abc
from types import ModuleType

pprint(isinstance(abc,ModuleType))

Output:

True

Summary #

A Python module is an object loaded from a file.

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