PCEP Practice Test 2 — 30 Questions

Question 1

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 2

Which TWO of the following expressions will evaluate to True?

Accepted Answer

3 == 3.0. In Python, the '==' operator compares values, and since integers and floats are compared by numeric value, 3 and 3.0 are numerically equal, so the expression evaluates to True. Option E is correct because 'is' checks object identity, and small integers like 3 are interned by Python, meaning they refer to the same object in memory, so '3 is 3' returns True.

Answer

3 is not 3

Answer

3 > 2 and 2 > 3

Answer

3 != 3.0

Question 3

What is the output of print(10 // 3, 10 % 3)?

Accepted Answer

3 1. The // operator performs floor division, which divides 10 by 3 and discards the fractional part, yielding 3. The % operator returns the remainder of that division, which is 1. The print function outputs both values separated by a space, resulting in '3 1'.

Answer

1 3

Answer

3.33 1

Answer

3 3

Question 4

Which of the following is an immutable data type in Python?

Accepted Answer

tuple. A tuple is immutable because once created, its elements cannot be changed, added, or removed. This is enforced by Python's internal structure: tuples are stored as a fixed-length array of object references, and no methods exist to modify them in place.

Answer

set

Answer

list

Answer

dict

Question 5

A dictionary student = {'name': 'John', 'age': 20}. To safely get the grade with a default of 'N/A', which code should be used?

Accepted Answer

student.get('grade', 'N/A'). The `get()` method of a dictionary safely retrieves the value for a given key, returning a default value (here `'N/A'`) if the key does not exist. This avoids raising a `KeyError` when the key `'grade'` is missing from the dictionary.

Answer

student['grade']

Answer

student.fetch('grade', 'N/A')

Answer

student['grade'] or 'N/A'

Question 6

What is the output of the following code?

def greet(name, greeting='Hello'):
    print(greeting, name)

greet('Alice')

Accepted Answer

Hello Alice. The function `greet` has a default parameter `greeting='Hello'`. When called with only one argument (`'Alice'`), the default value is used for `greeting`, so the output is `Hello Alice`. The `print` function outputs both arguments separated by a space.

Answer

Hello

Answer

SyntaxError

Answer

Alice

Question 7

Which TWO operators in Python yield an integer result when applied to two integers?

Accepted Answer

//. The floor division operator (//) always returns an integer result when both operands are integers, discarding any fractional part. For example, 7 // 2 yields 3, not 3.5. This is because floor division performs integer division and truncates toward negative infinity, ensuring the result type is int when both inputs are int.

Answer

**

Answer

*

Answer

/

Question 8

You are maintaining a legacy Python 2.7 script that calculates shipping costs. The script reads weight from user input, then calculates cost as weight * 1.5. Recently, the company upgraded to Python 3.9, and now the script raises a TypeError: can't multiply sequence by non-int of type 'float'. The input line is: weight = input('Enter weight: '). You need to fix the script minimally. Which action should you take?

Accepted Answer

Change the input line to weight = float(input('Enter weight: ')). In Python 3.9, `input()` returns a string, not a number. Multiplying a string by a float raises a TypeError. Option D converts the input to a float immediately, which is the minimal fix because it handles both integer and decimal weights correctly without changing the multiplication logic.

Answer

Use Python 2 style input by importing from __future__

Answer

Change the multiplication to cost = float(weight) * 1.5

Answer

Change the input line to weight = int(input('Enter weight: '))

Question 9

A junior developer is working on a script that processes user data. The script reads a CSV file into a list of dictionaries. Each dictionary represents a user with keys 'name', 'age', and 'email'. The developer needs to filter out users under 18 and store their names in a list. The current code is:

users = [{'name': 'Alice', 'age': 17, 'email': 'alice@example.com'}, {'name': 'Bob', 'age': 22, 'email': 'bob@example.com'}]

minors = []
for user in users:
    if user['age'] < 18:
        minors.append(user['name'])

print(minors)

The code works, but the senior developer says it is not idiomatic and suggests a more concise solution. Which of the following approaches is the best replacement?

Accepted Answer

minors = [user['name'] for user in users if user['age'] < 18]. It uses a list comprehension to directly extract the 'name' field from each user dictionary where the age is under 18, making the code concise and Pythonic. The original code works but is verbose; list comprehensions are the idiomatic Python approach for transforming and filtering iterables in a single readable line.

Answer

minors = []
for i in range(len(users)):
    if users[i]['age'] < 18:
        minors.append(users[i]['name'])

Answer

minors = [user for user in users if user['age'] < 18]

Answer

minors = list(map(lambda u: u['name'], filter(lambda u: u['age'] < 18, users)))

Question 10

Based on the exhibit, which expression returns 2.5 in Python?

Accepted Answer

5 / 2. The division operator `/` in Python always returns a float, even when dividing two integers. Since 5 divided by 2 equals 2.5, the expression `5 / 2` returns the float `2.5`.

Answer

int(5 / 2)

Answer

5 % 2

Answer

5 // 2

Question 11

A programmer is writing a script to read a number, determine if it is even or odd, and then also use the number to calculate its square. The code:

num = input("Enter a number: ")
if num % 2 == 0:
    print("Even")
else:
    print("Odd")
square = num ** 2
print("Square:", square)

When run, a TypeError occurs on the modulo line. Which fix will resolve the error and allow the later calculation to work?

Accepted Answer

Change the input to: num = int(input("Enter a number: ")). The `input()` function always returns a string, and the modulo operator `%` and exponentiation operator `**` require numeric operands. By converting the input to an integer with `int(input(...))`, both the modulo and exponentiation operations work correctly, resolving the TypeError and allowing the square calculation to proceed.

Answer

Change the condition to: if num // 2 == 0:

Answer

Change the condition to: if float(num) % 2 == 0:

Answer

Change the condition to: if int(num) % 2 == 0:

Question 12

A system administrator wrote a Python script to monitor disk usage. The script reads the output of a system command that returns a string like 'Used: 45%' and extracts the percentage. The code uses slicing to get the numeric part and converts to int. However, on some servers, the output format changes to 'Used: 45.2%', causing a ValueError when converting to int. The administrator needs a robust solution that works with both integer and floating-point percentages while still producing an integer result (e.g., 45 for 45.2%). Which option is the best approach?

Accepted Answer

Use a try-except block to attempt int conversion first; if a ValueError occurs, convert to float and then convert to int (which truncates the decimal part).. It uses a try-except block to first attempt int conversion for integer percentages, and if a ValueError occurs (due to a decimal point), it converts to float and then to int, which truncates the decimal part. This approach handles both '45%' and '45.2%' formats without raising an error, producing an integer result as required.

Answer

Use string splitting to extract the numeric part, then convert to float and round to the nearest integer.

Answer

Use a regular expression to extract the number and convert to float, then convert to int.

Answer

Use the .replace() method to remove the '%' character and then convert to int.

Question 13

What is the output of the following code?
```python
x = 10
y = 3
print(x // y * y + x % y)
```

Accepted Answer

10. The expression `x // y * y + x % y` is evaluated using integer arithmetic. First, `x // y` is floor division: 10 // 3 = 3. Then `3 * y` = 3 * 3 = 9. Then `x % y` = 10 % 3 = 1. Finally, 9 + 1 = 10, which is an integer. Option C is correct because the result is 10 (type int).

Answer

9

Answer

10.0

Answer

9.0

Question 14

A developer writes a script to calculate the average of three numbers: avg = (a + b + c) / 3. If a=5, b=10, c=15, what is the data type of avg?

Accepted Answer

float. In Python, the division operator (/) always returns a float, even when dividing integers that result in a whole number. Here, (5 + 10 + 15) / 3 equals 30 / 3, which yields 10.0, a float. Therefore, the data type of avg is float.

Answer

bool

Answer

int

Answer

str

Question 15

What is the output when the user enters 25?

Accepted Answer

2525. When the user enters 25, the input() function returns the string "25". The print() function then concatenates the string "25" with itself using the + operator, resulting in "2525". This is because the + operator performs string concatenation when both operands are strings, not numeric addition.

Answer

Error

Answer

25

Answer

50

Question 16

Refer to the exhibit. A beginner Python programmer executes the code and gets an error. What is the most likely cause?

Accepted Answer

The variables x and y are of incompatible types for the + operator. The error occurs when the + operator is used between incompatible types, such as a string (x) and an integer (y). In Python, the + operator performs concatenation for strings and addition for numbers, but mixing types without explicit conversion raises a TypeError. The code likely defines x as a string (e.g., '10') and y as an integer (e.g., 5), causing the error.

Answer

The + operator cannot be used with print()

Answer

The variable y should be converted to an integer using int()

Answer

The print function is misspelled

Question 17

Consider: x = True; y = False; z = x and not y or x. What is the value of z?

Accepted Answer

True. The expression `x and not y or x` is evaluated with operator precedence: `not` has the highest precedence, then `and`, then `or`. Given `x = True` and `y = False`, `not y` evaluates to `True`. Then `x and True` is `True and True`, which is `True`. Finally, `True or x` (where `x` is `True`) short-circuits to `True`. Thus, `z` is `True`.

Answer

None

Answer

Error

Answer

False

Question 18

Consider the following code:

def foo(x, y):
    return x * y

result = foo(y=2, 3)

What is the error?

Accepted Answer

A positional argument follows a keyword argument.. In Python, when calling a function, all positional arguments must appear before any keyword arguments. The call `foo(y=2, 3)` violates this rule by placing a positional argument (`3`) after a keyword argument (`y=2`), which raises a SyntaxError. This is enforced by Python's parser to avoid ambiguity in argument binding.

Answer

The function requires at least one argument but none provided.

Answer

Keyword arguments cannot be used in function calls.

Answer

The function definition has too many parameters.

Question 19

A programmer needs to swap the values of two variables a and b without using a temporary variable. Which approach works in Python?

Accepted Answer

a, b = b, a. Python supports tuple unpacking, which allows the values of a and b to be swapped in a single atomic operation: a, b = b, a. This works by creating a tuple (b, a) on the right-hand side, then unpacking it into the variables on the left, effectively swapping the values without a temporary variable.

Answer

a = b; b = a

Answer

a = a ^ b; b = a ^ b; a = a ^ b

Answer

a = b + a; b = a - b; a = a - b

Question 20

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.