PCEP Practice Test 3 — 25 Questions

Question 1

Which three of the following statements about lists are true? (Choose three.)

Accepted Answer

Lists can be indexed with integers.. Lists in Python are ordered sequences that support indexing with integers, starting from 0 for the first element and negative integers for reverse indexing. This allows direct access to any element by its position, a fundamental feature of sequence types in Python.

Answer

Lists have a fixed size once created.

Answer

Lists can only contain elements of the same data type.

Question 2

A developer is writing a program to calculate the average of three test scores. The current code reads scores as integers: a=int(input()); b=int(input()); c=int(input()); avg = (a+b+c)/3; print(avg). For scores 7, 8, and 9, the output is 8.0, but the requirement is to print the integer average (8), rounded to the nearest whole number. Which modification should the developer make to meet the requirement?

Accepted Answer

Use round(avg): print(round(avg)). The requirement is to print the integer average rounded to the nearest whole number. Using `round(avg)` correctly rounds the floating-point result (8.0) to the nearest integer (8) and prints it as an integer, satisfying the requirement. Option D is correct because `round()` performs standard rounding (banker's rounding in Python 3) and returns an integer when called with a single argument.

Answer

Use integer division after multiplying sum

Answer

Use integer division: avg = (a+b+c)//3

Answer

Use int(avg): print(int(avg))

Question 3

What is the output of print(type(3 + 4.5))?

Accepted Answer

. In Python, when you add an integer (3) and a float (4.5), implicit type conversion (coercion) occurs: the integer is promoted to a float to avoid data loss. The result is 7.5, which is a float. Therefore, type(7.5) returns .

Answer

Answer

Answer

Question 4

What is the output of the following code?
print('Hello', 'World', sep='-', end='!
')

Accepted Answer

Hello-World!
. The `print()` function with `sep='-'` replaces the default space separator with a hyphen between the two arguments 'Hello' and 'World', producing 'Hello-World'. The `end='!
'` parameter overrides the default newline-only end with an exclamation mark followed by a newline, so the output ends with '!' before the newline. Therefore, the correct output is 'Hello-World!
'.

Answer

Hello-World

Answer

Hello World!

Answer

Hello World!

Question 5

Which of the following variable names is valid in Python?

Accepted Answer

_private. (_private) is valid because Python allows variable names to start with an underscore. Identifiers can consist of letters, digits, and underscores, but must not begin with a digit. The underscore is treated as a letter, so _private conforms to Python's naming rules.

Answer

1st_value

Answer

class

Answer

my-var

Question 6

Refer to the exhibit. What is the output of the code?

Accepted Answer

4. The code iterates over the list `[1, 2, 3, 4]` and breaks out of the loop when `i == 3`, so only the first three iterations execute. The `else` clause on the `for` loop runs only if the loop completes without a `break`, so it is skipped. The final value of `i` after the loop is 3, but the code prints `i + 1`, which yields 4.

Answer

Loop ended normally
4

Answer

7

Answer

1

Question 7

Match each Python data type to its description.

Accepted Answer

int: Whole numbers. The correct matches are: A (int - whole numbers), B (float - numbers with decimal point), D (bool - Boolean values True or False). Option C (str) is incorrect because strings are immutable sequences of characters, not mutable collections. Option E (list) is incorrect because lists are mutable collections, not immutable sequences. Option F (tuple) is incorrect because tuples are immutable sequences, not mutable collections.

Answer

str: Ordered, mutable collection of items

Answer

list: Immutable sequence of characters

Answer

tuple: Ordered, mutable collection of items

Question 8

What is the result of the expression: (1 and 0) or (not False and True)?

Accepted Answer

True. 1 and 0 evaluates to 0 (falsy). not False evaluates to True, so not False and True evaluates to True. 0 or True evaluates to True (the last truthy value).

Answer

False

Answer

0

Answer

1

Question 9

Which of the following is NOT a valid variable name in Python?

Accepted Answer

2nd_var. Python variable names cannot start with a digit. The name '2nd_var' begins with '2', which violates Python's identifier naming rules. Valid variable names must start with a letter (a-z, A-Z) or an underscore (_), and can be followed by letters, digits, or underscores.

Answer

_myvar

Answer

myVar2

Answer

my_var

Question 10

Which three of the following are Python arithmetic operators? (Choose three.)

Accepted Answer

+. The plus sign (+) is a standard Python arithmetic operator used for addition. It performs numeric addition when both operands are numbers, and also supports string concatenation, but its primary role in arithmetic contexts is addition.

Answer

|

Answer

&

Question 11

Given the code: my_list = [1, 2, 3, 4, 5]. What is the output of print(my_list[-3:-1])?

Accepted Answer

[3, 4]. Python list slicing with negative indices counts from the end of the list. my_list[-3:-1] starts at index -3 (value 3) and goes up to but does not include index -1 (value 5), so it returns [3, 4].

Answer

[4, 5]

Answer

[2, 3]

Answer

[3, 4, 5]

Question 12

Which of the following correctly creates a tuple with a single element 5?

Accepted Answer

t = (5,). In Python, a tuple with a single element requires a trailing comma after the element. Without the comma, parentheses are treated as grouping operators for expression evaluation, not as a tuple literal. Thus, `t = (5,)` creates a tuple containing the integer 5.

Answer

t = (5)

Answer

t = (5)

Answer

t = (5, 5)

Question 13

What is the output of: print(2 ** 3 ** 2)?

Accepted Answer

512. In Python, the exponentiation operator ** is right-associative, meaning that `2 ** 3 ** 2` is evaluated as `2 ** (3 ** 2)`, not `(2 ** 3) ** 2`. First, `3 ** 2` equals 9, then `2 ** 9` equals 512. Thus, the correct output is 512.

Answer

12

Answer

64

Answer

256

Question 14

Which of the following is the most efficient (Pythonic) way to create a list of squares for numbers 0 through 9?

Accepted Answer

squares = [i*i for i in range(10)]. Uses a list comprehension, which is the most Pythonic and efficient way to create a list because it combines iteration and list construction in a single, readable expression. It avoids the overhead of repeated method calls (like `append`) and is faster than `map` with a lambda due to reduced function call overhead.

Answer

squares = []; for i in range(10): squares.append(i*i)

Answer

squares = list(map(lambda x: x*x, range(10)))

Answer

squares = (i*i for i in range(10))

Question 15

Which exception is raised when trying to access a dictionary key that does not exist?

Accepted Answer

KeyError. In Python, when you attempt to access a dictionary key that does not exist using square bracket notation (e.g., `my_dict['nonexistent']`), the interpreter raises a `KeyError`. This is the standard exception for missing dictionary keys, as defined in the Python language specification. The correct answer is A.

Answer

TypeError

Answer

ValueError

Answer

AttributeError

Question 16

A program needs to check if a number is both positive and even. Which expression correctly implements this?

Accepted Answer

if num > 0 and num % 2 == 0:. It uses the logical `and` operator to combine two conditions: `num > 0` (checks if the number is positive) and `num % 2 == 0` (checks if the number is even). Both conditions must be true for the overall expression to be true, which correctly implements the requirement of checking if a number is both positive and even.

Answer

if num > 0 or num % 2 == 0:

Answer

if num > 0 & num % 2 == 0:

Answer

if num > 0 and % 2 == 0:

Question 17

What is the result of bool(0) in Python?

Accepted Answer

False. The bool() function in Python converts any value to a Boolean. The integer 0 is considered a falsy value, so bool(0) returns False. This is because Python defines 0, None, empty collections, and False itself as falsy.

Answer

0

Answer

None

Answer

True

Question 18

Given the code:
```python
name = input('Enter your name: ')
print('Hello, ' + name)
```
If the user enters 'Alice', what is the output?

Accepted Answer

Hello, Alice. The `print('Hello, ' + name)` statement concatenates the string literal `'Hello, '` (which includes a trailing space) with the user input `'Alice'`, producing the output `Hello, Alice`. The `input()` function returns the exact string entered by the user without any extra quotes or formatting.

Answer

Hello,Alice

Answer

Hello, 'Alice'

Answer

Hello, Alice

Question 19

A Python program prompts the user for their age and stores it in a variable. Which is the correct way to convert the input to an integer?

Accepted Answer

age = int(input("Age: ")). The `input()` function in Python always returns a string, and to perform arithmetic operations or numeric comparisons, the string must be explicitly converted to an integer using the `int()` constructor. This is a fundamental requirement for type conversion in Python when handling user input.

Answer

age = str(input("Age: "))

Answer

age = float(input("Age: "))

Answer

age = input("Age: ")

Question 20

A server logs are stored as a list of tuples: `logs = [('2024-01-10', 'INFO', 'Started'), ('2024-01-10', 'ERROR', 'Disk full')]`. A developer wants to count how many ERROR logs exist. Which code snippet correctly counts them?

Accepted Answer

count = sum(log[1] == 'ERROR' for log in logs). Uses a generator expression with `sum()` to count how many tuples in the `logs` list have the second element equal to `'ERROR'`. The expression `log[1] == 'ERROR'` evaluates to `True` (which is treated as 1) or `False` (0) for each tuple, and `sum()` adds them up, giving the correct count of ERROR logs.

Answer

count = logs.count(('ERROR',))

Answer

count = [log for log in logs if log[1] == 'ERROR']

Answer

count = len(logs)