Error Handling in Python

Error handling allows your program to deal with unexpected situations without crashing. Python uses try, except, else, and finally blocks to handle runtime errors.

What is an Exception?

An exception is an error that occurs during program execution. If not handled, the program will stop abruptly.

x = 10
y = 0

print(x / y)  # ZeroDivisionError
        

Basic try / except

Use try and except to catch and handle errors.

try:
    x = 10
    y = 0
    print(x / y)
except ZeroDivisionError:
    print("Cannot divide by zero")
        

Handling Multiple Exceptions

You can handle different types of exceptions separately.

try:
    num = int("abc")
    print(num)
except ValueError:
    print("Invalid number")
except ZeroDivisionError:
    print("Division by zero")
        

Using else Block

The else block runs if no exception occurs.

try:
    num = int("123")
except ValueError:
    print("Conversion failed")
else:
    print("Conversion successful:", num)
        

Using finally Block

The finally block always runs, whether an exception occurs or not.

try:
    file = open("data.txt", "r")
    content = file.read()
except FileNotFoundError:
    print("File not found")
finally:
    print("Closing operation completed")