Python Input and Output Exercise: 20+ Coding Problems with Solutions

Whether you’re building interactive command-line applications, processing data, or working with files, a solid understanding of Python’s input and output (I/O) mechanisms is crucial. At its core, input is how a program receives data, while output is how it presents results to the user.

This article is a practical guide to mastering these essential skills. This article provides 20+ Python Input and Output practice questions that focus entirely on taking user input, displaying information, and interacting with files. You will also learn techniques for formatting output to present your data clearly and in a user-friendly way.

Each coding challenge includes a Practice Problem, Hint, Solution code, and detailed Explanation, ensuring you don’t just copy code, but genuinely practice and understand how and why it works.

• All solutions have been fully tested on Python 3.
• Interactive Learning: Use our Online Code Editor to solve these exercises in real time.

Exercise 1. Accept numbers from a user

Practice Problem: Write a program that accepts two integer numbers from the user and calculates their multiplication. Print the final result to the console.

Exercise Purpose: This exercise introduces the fundamental concept of user interaction. It teaches how to use the input() function to capture data and the importance of “type casting” (converting strings to integers) since all input starts as text.

Given Input:

• First Number: 10
• Second Number: 20

Expected Output: The multiplication is: 200

Help: Take user input in Python

# Accept input from user
num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))

# Calculate multiplication
res = num1 * num2

# Display result
print("The multiplication is:", res)Code language: Python (python)

Exercise 2. Display variables with a separator

Practice Problem: Use the print() function to format the words “Name”, “Is”, and “James” so they appear with three asterisks (***) between them.

Exercise Purpose: The print() function is more powerful than it looks. This exercise teaches the use of the sep (separator) keyword argument, which allows you to define how multiple items should be joined together in the output without manually typing strings.

Given Input:

• Strings: “Name”, “Is”, “James”

Expected Output:

Name***Is***James

# Using the sep parameter to join strings
print('Name', 'Is', 'James', sep='***')Code language: Python (python)

Exercise 3. Convert decimal number to octal

Practice Problem: Accept an integer from the user and display it as an octal number (Base 8).

Exercise Purpose: Computers often use different numbering systems (Hexadecimal, Octal, Binary). This exercise demonstrates how to use “Format Specifiers” in strings to automatically convert values between number systems for display.

Given Input: Decimal: 8

Expected Output:

The octal number of decimal number 8 is 10

num = 8
# Using %o to format the integer as octal
print('%o' % num)Code language: Python (python)

Exercise 4. Binary representation

Practice Problem: Accept an integer from the user and display its value in binary format (Base 2).

Exercise Purpose: Computers process everything in binary. This exercise shows how to use Python’s built-in formatting to visualize how a decimal number is represented at the hardware level using only 0s and 1s.

Given Input: Decimal Number: 45

Expected Output:

The binary representation of 45 is 101101

num = int(input("Enter a decimal number: "))

# Using f-string with the 'b' (binary) type code
binary_val = f"{num:b}"

print(f"The binary representation of {num} is {binary_val}")Code language: Python (python)

Exercise 5. Accept any three strings from one input() call

Practice Problem: Write a program that takes three names (or any words) from a user in a single input prompt and assigns them to three separate variables.

Exercise Purpose: Users dislike having to hit Enter three times for three pieces of data. This exercise teaches the split() method, the standard way to parse a single string into multiple data points based on whitespace.

Given Input: Emma Jessa Kelly

Expected Output:

Name1: Emma
Name2: Jessa
Name3: Kelly

# Taking multiple inputs in one go
str1, str2, str3 = input("Enter three names: ").split()

print('Name1:', str1)
print('Name2:', str2)
print('Name3:', str3)Code language: Python (python)

Exercise 6. Hexadecimal representation

Practice Problem: Accept an integer and display its value in hexadecimal format (Base 16).

Exercise Purpose: Hexadecimal is widely used in computing for memory addresses and color codes (e.g., #FFFFFF). This exercise teaches you how to bridge the gap between human-readable decimals and developer-centric hex values.

Given Input: Decimal Number: 255

Expected Output: The hexadecimal value is ff

num = int(input("Enter a number: "))

# :x produces lowercase (ff), :X produces uppercase (FF)
hex_val = f"{num:x}"

print(f"The hexadecimal value is {hex_val}")Code language: Python (python)

Exercise 7. Display float number with 2 decimal places

Practice Problem: Display a float number (a number with decimals) such as 458.541315 rounded to exactly two decimal places.

Exercise Purpose: Real-world data can be messy. This task is important for UI/UX and reporting because it helps make long, complex floating-point numbers easier to read.

Given Input: Number: 458.541315

Expected Output: 458.54

num = 458.541315

# Displaying 2 decimal places using formatting
print('%.2f' % num)Code language: Python (python)

Exercise 8. Percentage display

Practice Problem: Ask the user for a numerator and a denominator. Calculate the percentage (numerator/denominator * 100) and display it with exactly two decimal places followed by a percent sign.

Exercise Purpose: In this exercise, you will learn about string interpolation. You will practice combining math results with symbols like % and learn how to control the number of decimal places so your answers look neat.

Given Input:

• Numerator: 22
• Denominator: 29

Expected Output: The result is: 75.86%

num = int(input("Enter numerator: "))
den = int(input("Enter denominator: "))

percentage = (num / den) * 100

# Using f-string for precision and adding the '%' literal
print(f"The result is: {percentage:.2f}%")Code language: Python (python)

Exercise 9: Display right-aligned output

Practice Problem: Ask the user for a word and a number. Print the word right-aligned in a total field width of 20 characters, followed by the number.

Exercise Purpose: Good design is important. When you create text-based reports, lining up columns makes them easier to read. In this exercise, you will learn how to use Alignment Flags to set aside space on the screen and move text to the left, right, or center.

Given Input:

• Word: “Python”
• Number: 3.12

Expected Output:

               Python 3.14

word = input("Enter a word: ")
version = input("Enter a version number: ")

# Right-align the word in 20 spaces
print(f"{word:>20} {version}")Code language: Python (python)

Exercise 10. Center-aligned text

Practice Problem: Display a string centered within a 40-character field, using hyphens (-) as the padding character.

Exercise Purpose: Centering text is a common way to make headers or dividers in console reports. In this exercise, you will learn about the “Fill” and “Align” parts of f-string formatting.

Given Input: Text: “REPORT SUMMARY”

Expected Output:

-------------REPORT SUMMARY-------------

title = "REPORT SUMMARY"

# Center (^) with hyphen (-) as fill in a width of 40
formatted_title = f"{title:-^40}"

print(formatted_title)Code language: Python (python)

Exercise 11: Padding with zeros

Practice Problem: Ask the user for a number. Print this number padded with leading zeros so the total width is exactly 5 digits.

Exercise Purpose: This method is important when you need to create standardized IDs, serial numbers, or digital clock displays, such as showing “09” instead of “9” minutes. It shows you how to set a specific number format no matter the original input size.

Given Input: Number: 42

Expected Output: 00042

val = input("Enter your ID number: ")

# Method 1: Using zfill
print(val.zfill(5))

# Method 2: Using f-string (requires integer)
# print(f"{int(val):05}")Code language: Python (python)

Exercise 12: Format variables using string.format() method

Practice Problem: Given three variables quantity = 3, totalMoney = 450, and price = 150, use the format() method to print a sentence that neatly displays these values.

Exercise Purpose: Hard-coding strings with plus signs (+) is messy and error-prone. This exercise introduces the .format() method, a powerful way to inject variables into templates with precision and readability.

Given Input: quantity = 3, totalMoney = 450, price = 150

Expected Output:

I have 450 dollars so I can buy 3 football for 150.00 dollars.

quantity = 3
totalMoney = 450
price = 150
statement = "I have {1} dollars so I can buy {0} football for {2:.2f} dollars."

print(statement.format(quantity, totalMoney, price))Code language: Python (python)

Exercise 13. Currency formatting with commas

Practice Problem: Display a large number as currency, including a dollar sign, commas for thousands, and two decimal places.

Exercise Purpose: Financial applications require strict formatting. This exercise combines three concepts: prefixing, grouping (using commas), and precision to create a professional-grade money display.

Given Input: Amount: 1250500.7

Expected Output:

Total Balance: $1,250,500.70

balance = 1250500.7

# , adds commas, .2f adds two decimal places
formatted_balance = f"${balance:,.2f}"

print(f"Total Balance: {formatted_balance}")Code language: Python (python)

Exercise 14: Accept a list of 5 float numbers

Practice Problem: Write a program that accepts 5 float numbers as input from the user and stores them in a list.

Exercise Purpose: This exercise moves beyond single variables to “Data Structures.” It teaches how to use loops or list comprehension to efficiently handle multiple inputs and store them in a single list.

Given Input: Numbers: 78.6, 78.6, 85.3, 1.2, 3.5

Expected Output: [78.6, 78.6, 85.3, 1.2, 3.5]

Refer: Take a list as input in Python.

numbers = []

# Run a loop 5 times to get 5 inputs
for i in range(0, 5):
    print("Enter number at location", i, ":")
    item = float(input())
    numbers.append(item)

print("User List:", numbers)Code language: Python (python)

Exercise 15. Tabular output from lists

Practice Problem: You have two lists: names = ["Alice", "Bob", "Charlie"] and scores = [85, 92, 78]. Print these as a table with aligned columns.

Exercise Purpose: This exercise introduces “Parallel Iteration.” It teaches you how to step through two related lists simultaneously and format them to look like an organized database table.

Given Input:

• names = ["Alice", "Bob", "Charlie"]
• scores = [85, 92, 78]

Expected Output:

Name       Score
----------------
Alice      85   
Bob        92   
Charlie    78

names = ["Alice", "Bob", "Charlie"]
scores = [85, 92, 78]

print(f"{'Name':<10} {'Score'}")
print("-" * 15)

for name, score in zip(names, scores):
    print(f"{name:<10} {score}")Code language: Python (python)

Exercise 16. Interactive menu

Practice Problem: Create a menu that offers three options: “1. Say Hello”, “2. Calculate Square”, and “3. Exit”. The program should perform the action based on the number the user types.

Exercise Purpose: This is the foundation of “Command Line Interfaces” (CLI). It teaches you how to map user input to specific logic blocks using conditional statements, turning a linear script into an interactive application.

Given Input:

• Choice: 2
• Number to square: 5

Expected Output:

Enter choice (1-3): 2
Enter number to square: 5
The square is: 25

print("1. Say Hello\n2. Calculate Square\n3. Exit")
choice = input("Enter choice (1-3): ")

if choice == "1":
    print("Hello there! Hope you're having a great day.")
elif choice == "2":
    val = int(input("Enter number to square: "))
    print(f"The square is: {val * val}")
elif choice == "3":
    print("Exiting... Goodbye!")
else:
    print("Invalid choice. Please pick 1, 2, or 3.")Code language: Python (python)

Exercise 17. Masked password input (getpass)

Practice Problem: Write a script that asks a user for their username using standard input and their password using masked input (where the characters don’t appear on the screen).

Exercise Purpose: Security is paramount. Using input() for passwords is a major vulnerability because the password remains visible in the terminal’s scrollback buffer. The getpass module is the standard way to handle sensitive credentials by suppressing local echo.

Given Input:

• Username: admin
• Password: SecretPassword123 (invisible during typing)

Expected Output:

Enter Username: admin
Password: 
Login successful for admin!

import getpass

user = input("Enter Username: ")
# Characters will not be displayed as you type
pwd = getpass.getpass("Password: ")

if user == "admin" and pwd == "SecretPassword123":
    print(f"Login successful for {user}!")
else:
    print("Access Denied.")Code language: Python (python)

Exercise 18. Read a file and store its content in a list

Practice Problem: Read an existing file test.txt and store every line as an individual element in a Python list.

Exercise Purpose: It’s the first step in “Data Parsing”, taking raw text from a disk and converting it into a structured format (a list) that Python can easily sort, filter, or search.

Given Input: A file test.txt with multiple lines.

Expected Output: ['Line 1', 'Line', 'Line']

See:

• Python file handling
• Python Read file

# Read file content into a list
with open("test.txt", "r") as f:
    lines = f.readlines()
    print(lines)Code language: Python (python)

Exercise 19. Write list of strings to a file

Practice Problem: Take a list of favorite fruits and save each fruit onto a new line in a file named fruits.txt.

Exercise Purpose: In data science or web dev, you often process data in memory (as a list) and then need to “persist” it (save it to a disk). This exercise teaches you how to export structured Python data into a permanent text format.

Given Input:

• fruit_list = ["Apple", "Banana", "Cherry", "Date"]

Expected Output: A file fruits.txt created with each fruit on its own line.

Help: Python write file

fruit_list = ["Apple", "Banana", "Cherry", "Date"]

# Open file for writing
with open("fruits.txt", "w") as f:
    for fruit in fruit_list:
        f.write(fruit + "\n")

print("File 'fruits.txt' has been created successfully.")Code language: Python (python)

Exercise 20. Count total lines in a file

Practice Problem: Write a program that opens an existing text file and calculates exactly how many lines of text it contains.

Exercise Purpose: This is a fundamental “Data Auditing” task. Before you process a log file or a dataset, you need to know its size. This exercise teaches you how to iterate through a file object efficiently.

Given Input: A file sample.txt with 12 lines of text.

Expected Output: 12

line_count = 0

with open("sample.txt", "r") as f:
    for line in f:
        line_count += 1

print(f"The file contains {line_count} lines.")Code language: Python (python)

Exercise 21. Read line number 4 from a file

Practice Problem: Open a file and display only the fourth line of the content.

Exercise Purpose: Sometimes files are massive (gigabytes in size), and you only need a specific snippet. This exercise reinforces the idea that file lines can be treated like a list, allowing for direct, indexed access.

Given Input: A file test.txt containing:

Line 1
Line 2
Line 3
Line 4
Line 5

Expected Output: Line 4

See: Read Specific Lines From a File in Python

# Opening the file in read mode
with open("test.txt", "r") as f:
    # Read all lines into a list
    lines = f.readlines()
    # Print the 4th line (index 3)
    print(lines[3])Code language: Python (python)

Exercise 22. Check if file is empty

Practice Problem: Write a script that checks a file’s metadata. If the file size is 0 bytes, print “File is empty”; otherwise, print the size in bytes.

Exercise Purpose: Sometimes a file exists but contains no data (common in failed downloads or interrupted logs). This exercise introduces the os module and “system metadata”—information about a file rather than the content inside it.

Given Input: An empty file named empty_log.txt.

Expected Output:

Checking empty_log.txt...
Status: File is empty.

import os

filename = "empty_log.txt"

# Check if the file actually exists first to avoid errors
if os.path.exists(filename):
    file_info = os.stat(filename)
    if file_info.st_size == 0:
        print(f"Status: {filename} is empty.")
    else:
        print(f"Status: {filename} size is {file_info.st_size} bytes.")
else:
    print("File not found.")Code language: Python (python)

Exercise 23. Delete a specific file

Practice Problem: Write a program that asks the user for a filename and deletes it from the folder. Caution: This operation is permanent.

Exercise Purpose: File system maintenance. This exercise shows you how Python can perform high-level administrative tasks. It also emphasizes the importance of “High Risk” operations and the need to always verify the user’s intent.

Given Input: Filename to delete: old_data.csv

Expected Output:

Are you sure you want to delete 'old_data.csv'? (y/n): y
File 'old_data.csv' has been deleted.

import os

target = input("Enter filename to delete: ")

if os.path.exists(target):
    confirm = input(f"Are you sure you want to delete '{target}'? (y/n): ")
    if confirm.lower() == 'y':
        os.remove(target)
        print(f"File '{target}' has been deleted.")
    else:
        print("Operation cancelled.")
else:
    print("Error: File does not exist.")Code language: Python (python)