PCEP Practice Exam 2 — 20 Questions

Question 1

Which TWO of the following are valid variable names in Python? (Choose two.)

Accepted Answer

data1. 'data1' starts with a letter and contains only letters and digits, which is allowed by Python's identifier rules. Python variable names must begin with a letter (a-z, A-Z) or underscore, and can be followed by letters, digits, or underscores.

Answer

total$

Answer

my var

Answer

2nd_place

Question 2

Which TWO of the following are valid Python data types?

Accepted Answer

int. `int` is a built-in numeric data type in Python used to represent whole numbers without a fractional component. Python's `int` type has arbitrary precision, meaning it can handle arbitrarily large integers limited only by available memory.

Answer

string

Answer

char

Answer

double

Question 3

A function is defined as:
def add(a, b=5):
    return a + b
What is the result of add(10)?

Accepted Answer

15. The function `add(a, b=5)` defines a default value of 5 for parameter `b`. When called as `add(10)`, the argument 10 is assigned to `a`, and `b` uses its default value of 5. The function returns `10 + 5 = 15`, making option C correct.

Answer

10

Answer

5

Answer

Error

Question 4

A developer writes a function that takes a tuple as an argument and tries to modify an element inside the tuple. What happens?

Accepted Answer

The code raises a TypeError.. Tuples in Python are immutable, meaning their elements cannot be changed after creation. Attempting to modify an element (e.g., `my_tuple[0] = 5`) raises a `TypeError` because the tuple object does not support item assignment. This is a fundamental property of the tuple data type.

Answer

The tuple is converted to a list automatically.

Answer

The first element is modified successfully.

Answer

The code raises a ValueError.

Question 5

A program uses a variable named 'list' that shadows the built-in list type. Later, the code tries to create a new list using list([1,2,3]) but gets a TypeError. What is the most likely cause?

Accepted Answer

The variable 'list' is now an integer or other non-callable type.. When a variable named 'list' is assigned a value (e.g., an integer), it shadows the built-in `list` type in the current scope. Later, calling `list([1,2,3])` attempts to call the variable `list` as a function, but since it now holds a non-callable object (like an integer), Python raises a TypeError. This is a classic name-shadowing issue in Python.

Answer

The argument [1,2,3] is invalid because it contains integers.

Answer

The list constructor expects a tuple, not a list.

Answer

The code is missing an import for the list type.

Question 6

A developer wants to store a person's age. Which of these variable names is invalid?

Accepted Answer

3rd_age. In Python, variable names must start with a letter or an underscore, not a digit. Option B (`3rd_age`) begins with a digit, which violates Python's identifier naming rules and will raise a `SyntaxError` if used in code.

Answer

_age

Answer

Age

Answer

age_3

Question 7

A developer writes: a = 3; b = 4; c = a + b / 2. What is the value of c?

Accepted Answer

5.0. In Python, the division operator `/` always returns a float, and operator precedence dictates that division is performed before addition. Thus, `b / 2` evaluates to `4 / 2 = 2.0`, then `a + 2.0` yields `3 + 2.0 = 5.0`. Option D is correct because the result is a float value of 5.0.

Answer

3

Answer

3.5

Answer

5

Question 8

Which THREE of the following are valid ways to iterate over a list?

Accepted Answer

for i in mylist:. Python's `for i in mylist:` syntax directly iterates over each element of the list `mylist`, assigning the element value to the loop variable `i` in each iteration. This is the standard and most Pythonic way to traverse a list.

Answer

foreach i in mylist:

Answer

iter(mylist)

Question 9

Which TWO of the following are valid ways to create a tuple containing the elements 1 and 2? (Select two.)

Accepted Answer

tuple([1, 2]). `tuple([1, 2])` calls the `tuple()` constructor with a list `[1, 2]` as an argument, which converts the list into a tuple `(1, 2)`. Option E is correct because `(1, 2)` is the literal syntax for a tuple containing the elements 1 and 2.

Answer

(1)

Answer

[1, 2]

Answer

int(1)

Question 10

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 11

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 12

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 13

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 14

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 15

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 16

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 17

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 18

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)))