🐍 12.9 Mastering Exception Handling in Python: try - except - finally Made Easy!

Errors are inevitable while programming — but Python gives us smart tools to handle them gracefully. In this blog, you’ll learn what exceptions are, why they occur, and how to manage them using try, except, and finally blocks.

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🔹 What is an Exception?

Exception is an error that occurs during the execution of a program, disrupting its normal flow. These are not syntax errors, but runtime errors such as dividing by zero or accessing an invalid index in a list.

Without proper handling, exceptions can cause the entire program to crash.

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🚨 Common Exceptions in Python

• ZeroDivisionError: Raised when a number is divided by zero.
• IndexError: Occurs when trying to access an invalid list index.
• ValueError: Raised when a function gets the correct type but inappropriate value.
• TypeError: Raised when an operation is performed on incompatible types.
• KeyError: Raised when a key is not found in a dictionary.

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🧰 Handling Exceptions using try - except

To prevent the program from crashing, we use try-except blocks to catch and handle exceptions.

✅ Syntax:

try:
    # Code that may raise an exception
except ExceptionType:
    # Code to handle the exception

💡 Example:

try:
    num = int(input("Enter a number: "))
    result = 10 / num
    print("Result:", result)
except ZeroDivisionError:
    print("❌ Cannot divide by zero!")
except ValueError:
    print("❌ Invalid input. Please enter a number.")

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🔄 Using finally Block

The finally block is optional and contains code that runs no matter what — whether an exception occurred or not. It is often used to release resources like files or network connections.

✅ Syntax:

try:
    # risky code
except:
    # handle error
finally:
    # cleanup code (always runs)

💡 Example:

try:
    f = open("data.txt", "r")
    print(f.read())
except FileNotFoundError:
    print("❌ File not found.")
finally:
    print("✔️ Closing file (if opened).")

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🧾 Summary Table: Exception Handling Blocks

Block	Purpose
try	Contains code that may raise an exception
except	Catches and handles the exception
finally	Runs code regardless of exception (cleanup tasks)

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📝 Summary

• Exceptions are runtime errors that disrupt program execution.
• try-except blocks help handle these exceptions gracefully.
• finally is used for cleanup activities and always runs.

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💡 Tip: Never ignore exceptions! Handling them smartly can make your code robust and error-resilient.

Let Python throw errors — you just catch and handle them like a pro! 🧠🐍