Exceptions and Error Handling

"""Lesson 8: Exceptions and Error Handling

This lesson explains how Python handles errors so your programs can recover gracefully.
"""

A function that can raise an error if the input is invalid.

def divide(a, b):
    try:
        result = a / b
    except ZeroDivisionError:
        print("Error: cannot divide by zero.")
        return None
    except TypeError:
        print("Error: inputs must be numbers.")
        return None
    else:
        return result
    finally:
        print("divide() completed.")

print(divide(10, 2))
print(divide(10, 0))
print(divide(10, "five"))

Real-world example: validate user input safely.

user_input = "42"
try:
    value = int(user_input)
    print("Converted value:", value)
except ValueError:
    print("Please enter a valid integer.")