PCEP Functions, Tuples, Dictionaries and Exceptions Practice Test 3 — 15 Questions

Question 1

A developer is using a lambda function that takes two arguments and returns their sum. Which of the following lambda expressions is correct?

Accepted Answer

lambda a, b: a + b. Option A correctly defines a lambda function that takes two arguments and returns their sum. Option B is a valid lambda but returns the difference (a - b), not the sum, so it does not meet the requirement. Option C is incorrect because lambda expressions cannot include a `return` statement; the result is implicitly returned. Option D uses `def` to define a named function, not a lambda.

Answer

lambda a, b: a - b

Answer

lambda a, b: return a + b

Answer

def add(a, b): return a + b

Question 2

What does the following code output?

try:
    x = int('abc')
except ValueError:
    print('Invalid')

Accepted Answer

Invalid. The code attempts to convert the string 'abc' to an integer using int(). Since 'abc' is not a valid integer, Python raises a ValueError. The except block catches this specific exception and executes print('Invalid'), so the output is 'Invalid'. Option B is correct because the exception is handled gracefully without crashing.

Answer

The program crashes

Answer

(Nothing printed)

Answer

abc

Question 3

Given the tuple t = (1, 2, 3, 4, 5), which expression returns the last element?

Accepted Answer

t[-1]. In Python, negative indices count from the end of a sequence. For the tuple t = (1, 2, 3, 4, 5), t[-1] accesses the last element (5), because -1 refers to the final position. This is a standard feature of Python's sequence indexing.

Answer

t[5]

Answer

t[4]

Answer

t[0]

Question 4

Which of the following will raise a TypeError?

Accepted Answer

t = (1, 2); t[0] = 3. Tuples are immutable in Python; attempting to assign a value to an element using indexing (e.g., `t[0] = 3`) raises a `TypeError` with the message 'tuple' object does not support item assignment. This is a fundamental property of the tuple data type, designed to create fixed sequences that cannot be changed after creation.

Answer

lst = [1, 2]; lst.extend([3, 4])

Answer

x = {1, 2} & {2, 3}

Answer

d = {'a': 1}; d['b'] = 2

Question 5

Which TWO of the following are valid ways to create a dictionary with initial key-value pairs? (Select exactly 2)

Accepted Answer

d = {'a': 1, 'b': 2}. It uses the standard literal syntax for creating a dictionary with initial key-value pairs. The curly braces `{}` with colon-separated keys and values are the most common and direct way to define a dictionary in Python.

Answer

d = ('a'=1, 'b'=2)

Answer

d = dict.fromkeys(['a', 'b', 'c']) # without value

Answer

d = dict(['a', 'b'], [1, 2])

Question 6

Which of the following statements about function arguments are true? (Select all that apply)

Accepted Answer

Keyword arguments can be passed in any order, regardless of their position in the function definition.. The correct statements are A, B, D, and E. Keyword arguments can be passed in any order because they are matched by name (A). The **kwargs parameter collects additional keyword arguments into a dictionary (B). The *args parameter collects additional positional arguments into a tuple (D). Default arguments are evaluated once at function definition time (E). Option C is incorrect because *args must always appear before **kwargs in a function definition.

Answer

The *args parameter must always come after **kwargs in a function definition.

Question 7

Which TWO of the following exceptions are built-in Python exceptions? (Select exactly 2)

Accepted Answer

ZeroDivisionError. ZeroDivisionError is a built-in Python exception that is raised when the second operand of a division or modulo operation is zero. It is part of Python's standard exception hierarchy and is commonly encountered in arithmetic operations.

Answer

StringError

Answer

NumberError

Answer

ListError

Question 8

Based on the exhibit, where did the exception originate?

Accepted Answer

At line 5 in the divide function inside app.py.. The exception (ZeroDivisionError) originates at line 5 inside the divide function in app.py, where the code attempts to divide by zero. The traceback shows the innermost frame first, indicating the exact line where the error was raised.

Answer

In the main module outside any function.

Answer

In the ZeroDivisionError exception handler.

Answer

At line 10 in app.py, where the function was called.

Question 9

What is the output of the code in the exhibit?

Accepted Answer

{'apple':5, 'banana':6, 'cherry':6}. The code creates a dictionary using the `dict()` constructor with a list of tuples. Each tuple is a key-value pair. The keys are strings ('apple', 'banana', 'cherry') and the values are integers (5, 6, 6). The resulting dictionary is {'apple':5, 'banana':6, 'cherry':6}.

Answer

{5:'apple', 6:'banana', 6:'cherry'}

Answer

{'apple':5, 'banana':7, 'cherry':6}

Answer

{0:'apple', 1:'banana', 2:'cherry'}

Question 10

What is the output of the code?

Accepted Answer

Key not found. The code uses a dictionary's `get()` method with a default value of 'Key not found'. When the key 'b' is not present in the dictionary `d`, `get()` returns the specified default instead of raising an exception. Therefore, the output is 'Key not found', making option D correct.

Answer

AttributeError

Answer

The program exits with no output

Answer

None

Question 11

A developer wants to use a tuple to store the names of the months. They attempt to change an element: months = ("Jan","Feb","Mar"); months[1] = "Februar". What is the result?

Accepted Answer

A TypeError is raised. Tuples in Python are immutable, meaning their elements cannot be changed after creation. Attempting to assign a new value to an index of a tuple (e.g., months[1] = "Februar") raises a TypeError, not a ValueError or AttributeError. This is because the assignment operation is not supported for tuple objects.

Answer

The tuple is updated to ("Jan","Februar","Mar")

Answer

A ValueError is raised

Answer

An AttributeError is raised

Question 12

A developer writes a function that appends an item to a list: def add_item(item, my_list=[]): my_list.append(item); return my_list. They call add_item(1) twice. What are the return values of the two calls?

Accepted Answer

[1] and [1,1]. The default argument `my_list=[]` is evaluated only once at function definition time, not each time the function is called. Therefore, the first call `add_item(1)` appends 1 to the same list object, returning `[1]`. The second call appends another 1 to that same list, returning `[1, 1]`. This is a classic Python gotcha involving mutable default arguments.

Answer

[1] and [1]

Answer

TypeError

Answer

[1] and [2]

Question 13

In a try-except block, a developer has two except clauses: except ValueError: and except: (bare except). If the code in the try block raises a ValueError, which except clause is executed?

Accepted Answer

The ValueError except clause. When a ValueError is raised in the try block, Python searches the except clauses in the order they appear. It finds the first matching clause, which is `except ValueError:`, and executes it. The bare `except:` clause is only reached if no preceding named except clause matches the exception type.

Answer

Both in order

Answer

Neither; program crashes

Answer

The bare except clause

Question 14

Given a list of names = ['Alice', 'Bob', 'Charlie'], a developer wants to create a dictionary mapping each name to its length. Which expression accomplishes this?

Accepted Answer

{name: len(name) for name in names}. It uses a dictionary comprehension that iterates over each name in the list, using the name as the key and the result of `len(name)` as the value. This directly maps each name to its length, which is exactly what the developer wants.

Answer

{len(name): name for name in names}

Answer

{name: len for name in names}

Answer

{name: length for name in names}

Question 15

A function is defined as: def min_max(nums): return min(nums), max(nums). What type of value does it return?

Accepted Answer

A tuple. The function `min_max` uses `return min(nums), max(nums)`, which is a comma-separated list of expressions. In Python, when multiple values are returned separated by commas, they are automatically packed into a tuple. Therefore, the function returns a tuple containing the minimum and maximum values.

Answer

A set

Answer

A dictionary

Answer

A list