Python comes with a vast standard library, a collection of modules that provides implementations of commonly used functionalities. Besides these, there are numerous third-party modules available, providing even more capabilities.
What is a Module?
A module is a file containing Python definitions and statements. The file name is the module name with the suffix .py added. We define functions, classes, and variables in a module, and we can also include runnable code.
How to Import a Module?
To use any module in your Python code, you must first import it. Importing a module essentially means loading it into memory and making its functionalities accessible to your code. Here’s the basic syntax for importing a module:
import module_name
For example, to import the built-in math module, you would write:
import math
Now you can use functions from the math module, like math.sqrt to calculate the square root of a number:
import math print(math.sqrt(25)) # prints: 5.0
Importing Specific Items from a Module
To import a specific function or variable from a module, you can use the from keyword:
from module_name import item_name
For example, to import only the sqrt function from the math module, you would write:
from math import sqrt print(sqrt(25)) # prints: 5.0
Renaming a Module at Import
You can rename a module when importing it by using the as keyword. This is commonly done for modules with longer names:
import module_name as alias
For example, the numpy module is often aliased as np:
import numpy as np print(np.sqrt(25)) # prints: 5.0
Python Standard Library
Python’s standard library is a collection of modules that provides access to operations that aren’t part of the core Python language but are included in every Python installation. It includes modules for file I/O, system calls, string management, internet protocols, and more.
For example, here’s how you might use the random module from the standard library to generate a random number:
import random print(random.randint(1, 10)) # prints: a random integer between 1 and 10
In conclusion, modules and libraries are what make Python a powerful and versatile language. By importing and utilizing different modules, you can vastly extend Python’s capabilities without having to write a lot of code yourself.