PCEP Practice Test 12 — 15 Questions

Question 1

What is the data type of the expression (3.14 > 2) and ('a' < 'b')?

Accepted Answer

bool. The expression (3.14 > 2) evaluates to True because 3.14 is greater than 2, and ('a' < 'b') evaluates to True because in Python string comparison uses lexicographic order based on Unicode code points ('a' has code point 97, 'b' has 98). The 'and' operator combines these two Boolean values, resulting in True, which is of type bool. Therefore, the entire expression's data type is bool.

Answer

float

Answer

str

Answer

int

Question 2

Which of the following is an invalid variable name in Python?

Accepted Answer

my-var. 'my-var' contains a hyphen, which is not allowed in Python variable names. Python identifiers can only include letters, digits, and underscores, and cannot start with a digit. The hyphen is interpreted as a minus operator, making 'my-var' a syntax error.

Answer

_myVar

Answer

myVar

Answer

my_var

Question 3

Which operator is used to check if two values are equal in Python?

Accepted Answer

==. The == operator is Python's equality comparison operator, used to check if two values are equal. It returns True if the values are equal and False otherwise, making it the standard way to test equality in conditions and expressions.

Answer

=

Answer

eq

Answer

!=

Question 4

Refer to the exhibit. What is the output?

Accepted Answer

3 1. The code in the exhibit is `print(10//3, 10%3)`. The `//` operator performs floor division, which for positive numbers truncates the decimal part, so `10//3` yields 3. The `%` operator returns the remainder of the division, `10%3` yields 1. Thus the output is '3 1'.

Answer

3.0 1.0

Answer

3 3

Answer

3.333 1

Question 5

A junior developer writes: print('Hello' + 5). This code raises an error. What is the best way to fix it?

Accepted Answer

print('Hello' + str(5)). Python's `+` operator for strings requires both operands to be strings. The code `print('Hello' + 5)` raises a `TypeError` because it attempts to concatenate a string with an integer. Using `str(5)` converts the integer to the string `'5'`, allowing the concatenation to succeed and print `Hello5`.

Answer

print('Hello' * 5)

Answer

print('Hello', 5)

Answer

print('Hello' + '5')

Question 6

Which TWO data types are immutable in Python?

Accepted Answer

str. Option A (str) is correct because Python strings are immutable: once created, their characters cannot be changed in place, and operations like concatenation or replace() return new string objects rather than modifying the original. Option E (int) is correct because integers are immutable numeric objects; any arithmetic operation such as x += 1 rebinds the name to a new int object instead of altering the existing one. The unmarked options do not belong because set (B), list (C), and dict (D) are all mutable container types whose contents can be modified in place via methods like add(), append(), and item assignment.

Answer

set

Answer

list

Answer

dict

Question 7

Arrange the steps to write and run a Python script from the command line in the correct order.

Accepted Answer

Write the script in a text editor, save the file with a .py extension, open a terminal or command prompt, navigate to the directory containing the script, run the script using the Python interpreter.. The process involves creating the script, saving it, opening a terminal, navigating to its location, and executing it with the Python interpreter.

Answer

Write the script in a text editor, save the file with a .py extension, open a terminal or command prompt, run the script using the Python interpreter.

Answer

Write the script in a text editor, open a terminal or command prompt, run the script using the Python interpreter, save the file with a .py extension.

Answer

Write the script in a text editor, open a terminal or command prompt, navigate to the directory containing the script, run the script using the Python interpreter.

Question 8

A program contains a nested while loop. The inner loop should run as long as a condition is True, but the outer loop should stop after 3 iterations. Which code structure is correct? (Assume the inner loop condition is inner < 5.)

Accepted Answer

outer = 0
while outer < 3:
    inner = 0
    while inner < 5:
        # do something
        inner += 1
    outer += 1. Ly implements a nested while loop where the inner loop runs while `inner < 5` and the outer loop runs while `outer < 3`. The inner loop increments `inner` to control its own termination, and the outer loop increments `outer` after the inner loop completes, ensuring exactly 3 iterations of the outer loop. This matches the requirement that the outer loop stops after 3 iterations while the inner loop runs as long as its condition is True.

Answer

for outer in range(3):
    inner = 0
    while inner < 5:
        # do something
        inner += 1

Answer

outer = 0
while outer < 3:
    for inner in range(5):
        # do something
        outer += 1

Answer

outer = 0
while outer < 3:
    inner = 0
    while inner < 5:
        # do something
        outer += 1
        inner += 1

Question 9

A developer needs to iterate over a list of network interfaces and print only the names that start with 'eth'. Which code should be used?

Accepted Answer

for iface in interfaces: if iface.startswith('eth'): print(iface). The `startswith()` string method is the most direct and readable way to check if each interface name begins with the substring 'eth'. This approach avoids unnecessary slicing or substring membership checks, making the intent clear and the code efficient.

Answer

for i in range(len(interfaces)): if 'eth' in interfaces[i]: print(interfaces[i])

Answer

for iface in interfaces: if iface[:3] is 'eth': print(iface)

Answer

for iface in interfaces: if 'eth' in iface: print(iface)

Question 10

Which TWO of the following expressions evaluate to 0? (Select two.)

Accepted Answer

False * 1. In Python, False is a bool that behaves as the integer 0 in arithmetic, so 0 * 1 evaluates to 0. Option D (int(0.5)) is correct because int() truncates toward zero, discarding the fractional part of 0.5 and returning 0. Option B (5 // 2 * 2) evaluates to 4, since floor division 5 // 2 gives 2 and 2 * 2 is 4, not 0. Option C (True == 0) evaluates to False, because True equals 1, not 0. Option E (5 % 2) evaluates to 1, the remainder of 5 divided by 2, so it is not 0.

Answer

5 // 2 * 2

Answer

True == 0

Answer

5 % 2

Question 11

A developer writes code to iterate over a list and break when a certain condition is met. Which keyword is used to exit the loop prematurely?

Accepted Answer

break. The `break` keyword is used in Python to immediately exit the nearest enclosing loop (for or while) when a specified condition is met, allowing the program to resume execution at the next statement after the loop. This is the standard mechanism for premature loop termination in Python, as defined in the language specification.

Answer

stop

Answer

exit

Answer

continue

Question 12

A function `def process(data):` modifies the dictionary passed as argument by adding a new key. The developer wants to avoid modifying the original dictionary. What should the function do?

Accepted Answer

Create a copy of the dictionary at the start: `data = data.copy()`. Dictionaries are mutable objects in Python, so passing a dictionary to a function passes a reference to the same object. Calling `data.copy()` creates a shallow copy of the dictionary, allowing the function to modify the copy without affecting the original dictionary. This is the standard Pythonic way to avoid side effects on mutable arguments.

Answer

Add the key, then delete it at the end.

Answer

Modify directly; changes to mutable objects are local only.

Answer

Convert the dictionary to a tuple before processing.

Question 13

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 14

A programmer writes code that uses a while loop to process user input until the user types 'exit'. The code currently prints 'Done' after the loop, but it never exits. What is the most likely cause?

Accepted Answer

The variable controlling the loop is not updated inside the loop. If the variable controlling the loop (e.g., the user's input) is never updated inside the while loop, the loop condition will never become false, causing an infinite loop. In this scenario, the programmer likely reads input once before the loop but does not call input() again inside the loop to update the variable, so the loop never sees the 'exit' value.

Answer

The loop condition is 'while True'

Answer

The print statement is indented incorrectly

Answer

The input function is called outside the loop

Question 15

Which THREE of the following expressions evaluate to True?

Accepted Answer

3 == 3. Option A (3 == 3) is correct because the equality operator compares the two integer literals 3 and 3, which are identical, so the expression evaluates to True. Option C ('a' < 'b') is correct because Python compares strings lexicographically by Unicode code point, and the code point of 'a' (97) is less than that of 'b' (98), yielding True. Option E (2 != 1) is correct because the inequality operator returns True when the operands differ, and 2 is not equal to 1. Option B (1 < 0) is not correct because 1 is greater than 0, so the less-than comparison evaluates to False. Option D (4 > 5) is not correct because 4 is less than 5, so the greater-than comparison evaluates to False.

Answer

1 < 0

Answer

4 > 5