PCEP Certification Practice: KeyError

Question 1: Which of the following best describes the KeyError exception in Python?

1. Raised when trying to access a list index that is out of range.
2. Raised when a non-existent key is accessed in a dictionary.
3. Raised when an undefined variable is referenced.
4. Raised when an invalid type is passed to a function.

Question 2: Which of the following operations can raise a KeyError? (Select all that apply.)

• Accessing a non-existent key in a dictionary.
• Trying to delete a key that does not exist in a dictionary.
• Accessing an out-of-range index in a list.
• Trying to reference an undefined variable.

Question 3: The _________ exception is raised when trying to access a key that does not exist in a Python dictionary.

1. IndexError
2. KeyError
3. LookupError

Question 4: The __________ exception is raised when you attempt to access a key that is not present in a dictionary.

Question 5: Fill in the blank to catch the KeyError when accessing a missing key in a dictionary:

my_dict = {"name": "Alice", "age": 30}
try:
    print(my_dict["address"])
except __________:
    print("Key not found in dictionary")

Question 6: What will happen when you try to access a non-existent key in a Python dictionary?

1. The program will return None.
2. The program raises a KeyError.
3. The program raises an IndexError.
4. The program will print a default value.

Question 7: Insert the correct exception handling code to catch a KeyError when a dictionary key is missing:

my_dict = {"fruit": "apple", "color": "red"}
try:
    print(my_dict["price"])
except __________:
    print("The key does not exist!")

Question 8: Which of the following scenarios can raise a KeyError in Python? (Select all that apply.)

1. Accessing a non-existent key in a dictionary.
2. Using .pop() on a dictionary with a non-existent key and no default value.
3. Accessing an out-of-range index in a tuple.
4. Trying to delete a key that doesn’t exist in a dictionary.

Question 9: The _________ exception is raised when using the get() method of a dictionary with a missing key and no default value is provided.

• KeyError
• IndexError
• No exception is raised.

Question 10: When trying to access a key that does not exist in a dictionary using [], Python raises a __________ exception.

Question 11: Arrange the following exceptions in the correct order, from the highest level to the lowest in the Python exception hierarchy.

1. KeyError
2. LookupError
3. BaseException

Question 12: Which of the following are true about the KeyError exception in Python? (Select all that apply.)

1. It is raised when a dictionary key is missing.
2. It is a subclass of LookupError.
3. It is raised when an index is out of range in a list.
4. It is raised when using .get() on a dictionary with a missing key.

Question 13: The abstract exception _________ is the base class for exceptions raised during a failed key or index lookup.

1. IndexError
2. LookupError
3. KeyError

Question 14: Trying to access a missing key in a dictionary using square brackets ([]) raises a __________ exception.

Question 15: Fill in the blank to handle a KeyError raised when trying to delete a missing key from a dictionary:

my_dict = {"name": "Alice", "age": 25}
try:
    del my_dict["gender"]
except __________ as e:
    print("Key error:", e)

Question 16: Which of the following dictionary methods can be used to safely access a key without raising a KeyError?

1. pop()
2. get()
3. setdefault()
4. del

Question 17: Insert the correct code to safely access a key in a dictionary without raising a KeyError:

my_dict = {"fruit": "apple", "color": "red"}
# INSERT CODE HERE to access key "price" safely
print(value)

Question 18: Which of the following operations can raise a KeyError in Python? (Select all that apply.)

1. Accessing a missing key using [] in a dictionary.
2. Using .pop() on a dictionary without providing a default value.
3. Accessing an out-of-bounds index in a list.
4. Trying to delete a key that does not exist in a dictionary.

Question 19: In Python, the _________ exception is raised when trying to access a key in a dictionary that does not exist.

1. KeyError
2. IndexError
3. TypeError

Question 20: Trying to access a key that does not exist in a dictionary raises a __________ exception.

Question 21: Sort the following exceptions in the correct order from the most general to the most specific.

1. LookupError
2. KeyError
3. BaseException

Question 22: Which of the following dictionary methods can prevent a KeyError when accessing a missing key? (Select all that apply.)

1. get()
2. pop()
3. setdefault()
4. []

Question 23: The exception _________ is raised when you attempt to access a key that does not exist in a dictionary using square brackets.

1. KeyError
2. IndexError
3. LookupError

Question 24: Fill in the blank to catch a KeyError raised when trying to access a missing key in a dictionary:

my_dict = {"name": "John", "age": 28}
try:
    print(my_dict["gender"])
except __________:
    print("Key does not exist")

Question 25: Which exception is raised when trying to access a non-existent key in a Python dictionary?

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