Python Error Handling Exercises With Answers

Which exception does int("abc") raise?

1. ValueErrorcorrect
2. TypeError
3. KeyError
4. IndexError

Answer: ValueError

Why: The text has the right type but an invalid value for int().

Which exception does a missing dictionary key raise?

1. NameError
2. SyntaxError
3. KeyErrorcorrect
4. ValueError

Answer: KeyError

Why: Square-bracket access on a missing key raises KeyError.

What is the main purpose of try/except?

1. To handle an expected failure and recovercorrect
2. To convert text to numbers
3. To hide every bug
4. To make code run faster

Answer: To handle an expected failure and recover

Why: A handler should catch a specific, predictable failure and choose a fallback.

When does a finally block run?

1. Only when the program exits
2. Always, after try and any except/else blockcorrect
3. Only after an exception
4. Only when try succeeds

Answer: Always, after try and any except/else block

Why: finally is used for cleanup that must happen either way.

Complete the exception type that handles a bad integer conversion.

try:
    value = int(text)
except ____:
    value = 0

Answer: ValueError

Why: int() raises ValueError when the text cannot be converted.

Complete the keyword that begins an exception handler.

try:
    value = int(text)
____ ValueError:
    value = 0

Answer: except

Why: except introduces the block that handles a matching exception.

Complete the exception type raised by a missing dictionary key.

try:
    price = order["price"]
except ____:
    price = 0

Answer: KeyError

Why: Reading a missing key with square brackets raises KeyError.

Complete the block that always runs for cleanup.

try:
    print("work")
____:
    print("cleanup")

Answer: finally

Why: finally runs whether the try succeeds or fails.

What is printed?

try:
    print(int("5"))
except ValueError:
    print("bad")

Answer: 5

Why: The conversion succeeds, so the except block is skipped.

What is the output?

try:
    print(int("x"))
except ValueError:
    print("invalid")

Answer: invalid

Why: The conversion fails, so the handler prints invalid.

What does this code print?

order = {}
try:
    print(order["price"])
except KeyError:
    print("missing")

Answer: missing

Why: The key is absent, so the KeyError handler runs.

What does the program output?

try:
    print("try", end=" ")
finally:
    print("finally")

Answer: try finally

Why: finally always runs, and the first print avoids a newline.