How does Exception Handling work in Python with try, except, else, and finally?

Explanation & Concept

• `try`: The block of code to monitor for exceptions. • `except SpecificError`: Catches and handles specific error types. • `else`: Executes only if **no exception** was thrown in the `try` block. • `finally`: Executes unconditionally, regardless of whether exceptions were caught.

Code Example

python

def calculate_average(items):
    try:
        total = sum(items)
        avg = total / len(items)
    except ZeroDivisionError:
        print("Cannot calculate average of an empty list.")
        return 0
    except TypeError as e:
        print(f"Invalid item type: {e}")
        return None
    else:
        print("Calculation successful!")
        return avg
    finally:
        print("Operation completed.")

How It Works & Key Takeaways

Using specific exception types prevents masking unexpected programming bugs that a bare `except:` would hide.

Exception HandlingIntermediate

1Question 1 of 2

python

How does Exception Handling work in Python with try, except, else, and finally?

Explanation & Concept

Code Example

python

def calculate_average(items):
    try:
        total = sum(items)
        avg = total / len(items)
    except ZeroDivisionError:
        print("Cannot calculate average of an empty list.")
        return 0
    except TypeError as e:
        print(f"Invalid item type: {e}")
        return None
    else:
        print("Calculation successful!")
        return avg
    finally:
        print("Operation completed.")

How It Works & Key Takeaways

Using specific exception types prevents masking unexpected programming bugs that a bare `except:` would hide.