Types of Exceptions in Python

Python

Learn Python Programming: A Beginner’s Guide to Coding, Automation, and Data Science

 

What is an Exception? 

An exception is like a sudden roadblock in your Python program.  If something unexpected happens (like dividing by zero or accessing an undefined variable), Python throws an exception and stops the program—unless you handle it! 

Common Python Exceptions 

Exception	When it Happens
SyntaxError	When Python doesn't understand your code (e.g., missing :)
NameError	When you use a variable that hasn’t been defined
TypeError	When you mix incompatible types (e.g., adding int and str)
ValueError	When a function gets an argument of the right type but wrong value
IndexError	When trying to access a list index that doesn’t exist
KeyError	When accessing a nonexistent dictionary key
ZeroDivisionError	When you try to divide by zero (which breaks math!)
FileNotFoundError	When you try to open a file that doesn’t exist

Examples of Common Exceptions

SyntaxError – The Grammar Police

print("Hello Python!"  # Oops! Missing closing parenthesis

NameError – Who’s That? 

print(hello_world)  # Variable hello_world is not defined!

TypeError – Mixing Apples and Oranges

print("Age: " + 25)  # Can't concatenate string and integer!

IndexError – Out of Bounds

numbers = [1, 2, 3]
print(numbers[5])  # No item at index 5!

KeyError – Missing Keys

dictionary = {"name": "Alice"}
print(dictionary["age"])  # No 'age' key in dictionary!

Handling Exceptions with try-except

To prevent program crashes, use try-except!

try:
    print(10 / 0)  # ZeroDivisionError!
except ZeroDivisionError:
    print("You can’t divide by zero!")

Summary

Python has many built-in exceptions, and handling them properly makes your programs more robust!

• Learn common exceptions (e.g., TypeError, ValueError, IndexError)
• Use try-except to handle errors gracefully
• Debug smarter and keep your program running smoothly!