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Built-in Modules in Python

Last Updated : 10 Apr, 2024
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Python is one of the most popular programming languages because of its vast collection of modules which make the work of developers easy and save time from writing the code for a particular task for their program. Python provides various types of modules which include Python built-in modules and external modules. In this article, we will learn about the built-in modules in Python and how to use them.

What are Python Built-in modules?

Python built-in modules are a set of libraries that come pre-installed with the Python installation. It will become a tedious task to install any required modules in between the process of development that’s why Python comes with some most used modules required. These modules provide a wide range of functionalities, from file operations and system-related tasks to mathematical computations and web services. The use of these modules simplifies the development process, as developers can leverage the built-in functions and classes for common tasks, providing code reusability, and efficiency. Some examples of Python built-in modules include “os”, “sys”, “math”, and “datetime”.

We can run the below command to get the all available modules in Python:


Python Built-in Modules

Advantages of built-in modules in Python

Reduced Development Time

Built-in modules in Python are made to perform various tasks that are used without installing external module or writing the lengthy code to perform that specific task. So, developers used them according to their convenience to save the time.

Optimized Performance

Some Python built-in modules are optimized for performance, using low-level code or native bindings to execute tasks efficiently.


These modules have been rigorously tested and have been in use by the Python community for years. As a result, they are typically stable and have fewer bugs compared to new or less well-known third-party libraries.


Python Built-in modules provide consistent way to solve problems. Developers familiar with these modules can easily understand and collaborate on codebases across different projects.


As these modules are part of the Python Standard Library, they establish a standard way of performing tasks.


Python’s official documentation is comprehensive and includes detailed explanations and examples for Python built-in modules. This makes it easier to learn and utilize them.


Python Built-in modules are maintained by the core Python team and community, regular updates, bug fixes, and improvements are to be expected, ensuring long-term viability.

Reduced Risk

Using third-party libraries can introduce risks, like discontinued support or security vulnerabilities.

Using Built-in Modules in Python

We have learned what are built-in modules in Python and their advantage. Now, let’s see the code example of built-in modules in Python and how we can use them in our Python code.

JSON Module in Python

“json” module in Python is used to encode and decode JSON data. JSON format is a widely used on the web to exchange the information. It is extremely useful for reading and writing data in the JSON format.


In the below example, we have used json module to convert the Python dictionary into JSON format. Firstly, we import the “json” module and then define the Python dictionary after that we convert the Python dictionary into JSON format using “json.dumps()” method of “json” module in Python and finally print the JSON data.


import json  
data = {
    "name": "Jonny",
    "age": 30,
    "is_student": True,
    "courses": ["Web Dev", "CP"]
json_string = json.dumps(data, indent=4)


    "name": "Jonny",
    "age": 30,
    "is_student": true,
    "courses": [
        "Web Dev",

Tkinter module in Python

“tkinter” is the standard GUI (Graphical User Interface) library in Python. “tkinter” module is used to create windows, buttons, text boxes, and other UI elements for desktop applications.


Firstly we imports the “tkinter” module as “tk” and defines a function, “on_button_click”, which updates a label’s text. A main GUI window titled “Tkinter Example” is created, containing a label and a button. The label displays “Click the button below”, and the button, labeled “Click Me”, triggers the previously defined function when pressed. The application remains responsive to user interactions by using the “root.mainloop()” event loop, allowing the label’s message to change upon button clicks.


import tkinter as tk  
def on_button_click():  
    label.config(text="Hello, Geeks!")
root = tk.Tk()
root.title("Tkinter Example")  
label = tk.Label(root, text="Click the button below")  
button = tk.Button(root, text="Click Me", command=on_button_click) 

Output: In the below output we can see that when we click on “Click Me” button the text changes.


Random module in Python

The “random” module in Python is used to generates random numbers and provides the functionality of various random operations such as ‘random.randint()’, ‘random.choice()’, ‘random.random()’, ‘random.shuffle()’ and many more.


In the below code, firstly we import the random module, then we are printing the the random number from “1 to 10” and random item from the list by using random.randint() and random.choice() methods of random module respectively.


import random  
num = random.randint(1, 10)
print(f"Random integer between 1 and 10: {num}")
fruits = ["Java", "C", "C++", "Python"]
chosen_fruit = random.choice(fruits)
print(f"Randomly chosen language: {chosen_fruit}")


Random integer between 1 and 10: 9
Randomly chosen language: Python

Math Module in Python

The math module offers mathematical functions used for advanced arithmetic operations. This includes trigonometric functions, logarithmic functions, and constants like pi and e. This module is used to perform complex calculations using Python program.


In the below example, we have used math module the find the square root of a number using math.sqrt() method and the value of PI using math.pi method and then print the result using print() function of Python.


import math
sqrt_val = math.sqrt(64)
pi_const = math.pi



datetime module in Python

The “datetime” module allows for manipulation and reading of date and time values. Some of the basic method of “datetime” module are “”, “datetime.time”, “datetime.datetime”, and “datetime.timedelta”.


In the below example, we have print the today’ date and current time by using method and method of “datatime” module in Python.


import datetime
date_today =
time_now =



OS module in Python

The “os” module in Python is used to interact with the operating system and offers OS-level functionalities. For example, interacting with file system, reading directory, and launching application.


In the below example, we have used “os” module to fetch the directory path using os.getcwd() method and then print the path.


import os
directory = os.getcwd()



sys Module in Python

The “sys” module in Python provides functions and variables that interact with the Python runtime environment. It allows developers to access Python interpreter attributes and manipulate them. It offers a range of other functionalities, such as input/output stream access, memory info access, and more.

In the below example, we have used sys module to print the current version of Python programming language and also print the list of command line arguments passed while running the Python program.


import sys
print("Python version:", sys.version)
print("Command line arguments:", sys.argv)

In the below output, we can see the current version is printed and command line arguments in the form of list along with the name of Python program name.


SYS Module in Python

The re module in Python provides support for working with regular expressions. Regular expressions (often abbreviated as “regex”) are powerful tools for matching strings or sets of strings using a specialized syntax that allows for flexible pattern matching.


In the below example, we write an simple example of finding the matching string using “re” module in Python. After importing “re” module we define a pattern and a text. We search for the email pattern that may present in the text using search() function and then print the first found email in the text. After that we find all occurrences of mails in the text and then print them.


import re
pattern = r"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}"
text = "Contact us at and for more details."
match =, text)
if match:
    print("First found email:",
emails = re.findall(pattern, text)
print("All found emails:", emails)


First found email:
All found emails: ['', '']

hashlib Module in Python

The “hashlib” module in Python provides algorithms for message digests or hashing. It allows for data integrity checks using algorithms like SHA-256, MD5, and more.


In this example, firstly, we import the hashlib module then define a sample message string. Convert the string into its SHA-256 hash representation using hashlib.sha256() function. Print the resulting hash.


import hashlib
message = "Hello, World!"
hashed = hashlib.sha256(message.encode()).hexdigest()



calendar Module in Python

The calendar module allows operations and manipulations related to calendars.


In this example, we print the October month of year 2023. Firstly, we import the “calendar” module. Generate a string representation of October 2023 using the month() function. Print the calendar for October 2023.


import calendar
cal_october = calendar.month(2023, 10)


    October 2023
Mo Tu We Th Fr Sa Su
 2  3  4  5  6  7  8
 9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31

heapq Module in Python

The “heapq” module in Python provides a collection of functions for implementing heaps based on regular lists. A heap is a special tree-based data structure that satisfies the heap property, and it is commonly used to implement priority queues.


In the below example, we have implemented the heap data structure using “heapq” module in Python and applied various heap methods on heap such as heapify(), heappush(), and heappop();


import heapq
numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5]
heapq.heappush(numbers, 7)
print(heapq.heappushpop(numbers, 8)) 
print(heapq.nlargest(3, numbers))  
print(heapq.nsmallest(3, numbers)) 


[9, 8, 7]
[2, 3, 3]


Python programming language offers a wide range of modules other than above modules that will help the Python developer, Data scientists, ML engineers and others. Python built-in modules make the work of programmers easy by terminating the problem of installing the Python modules again and again.

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