PCEP Practice Test 27 — 15 Questions

Question 1

A program checks divisibility. Which condition correctly determines if a number n is divisible by 7?

Accepted Answer

n % 7 == 0. The modulo operator (%) returns the remainder of the division of n by 7. If the remainder is 0, then n is exactly divisible by 7. This is the standard way to test divisibility in Python.

Answer

n / 7 == 0

Answer

n // 7 == 0

Answer

n % 7 != 0

Question 2

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 3

A Python developer is creating a function that processes a list of dictionaries and needs to ensure the original list remains unchanged. They write the following code:

def process(data):
    for item in data:
        item['processed'] = True
    return data

What is the best-practice critique of this function?

Accepted Answer

The function modifies the original list elements, causing side effects.. The function mutates the dictionaries in the original list by adding the key 'processed' to each one. This violates the principle of avoiding side effects in functions, as the caller's data is changed unexpectedly. In Python, dictionaries are mutable objects, so modifying them inside a function affects the original list elements.

Answer

The indentation should be 2 spaces instead of 4 to conform to PEP 8.

Answer

The function should use a list comprehension instead of a loop.

Answer

The function returns a value but does not use it, which is acceptable.

Question 4

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 5

You are an IT support specialist for a university. A professor uses a Python script that analyzes exam scores from a text file. The script calculates the average score and prints it. Recently, the script outputs 'NaN' instead of a number. The relevant code is: scores = [float(line.strip()) for line in open('scores.txt')]; average = sum(scores) / len(scores); print(average). You inspect the scores.txt file and find that one line contains the word 'Absent' and another line is blank. The professor wants the script to ignore non-numeric lines and blank lines, and also print a warning if any line was skipped. Which of the following modifications to the script best achieves this?

Accepted Answer

Open the file, iterate over lines, use try-except to convert to float, if successful append to list else increment a skip counter. At the end, print the average and the number of skipped lines.. It uses a try-except block to safely attempt conversion of each line to float, incrementing a skip counter for lines that fail (e.g., 'Absent' or blank). After processing, it computes the average only from successfully converted scores and prints both the average and the number of skipped lines, meeting the professor's requirements exactly.

Answer

Read all lines, filter with a lambda that checks if line can be converted to int, then convert to float.

Answer

Use list comprehension with condition if line.strip() != '': scores = [float(line.strip()) for line in open('scores.txt') if line.strip() != '']

Answer

Check if line.strip().isdigit() before conversion, and skip if not.

Question 6

A programmer writes: x = 5; y = x; x = 3; print(y). What is the output?

Accepted Answer

5. In Python, integers are immutable, and the assignment `y = x` copies the reference to the integer object 5, not the variable itself. When `x` is later reassigned to 3, `y` still points to the original integer object 5, so `print(y)` outputs 5.

Answer

3

Answer

8

Answer

None

Question 7

Which logical expression evaluates to True given that a = 5 and b = 10?

Accepted Answer

not (a > b). Given a = 5 and b = 10, the expression not (a > b) evaluates the inner comparison a > b, which is 5 > 10 = False, and then applies not, yielding True. This is the only option that evaluates to True with the given values. Understanding operator precedence and boolean negation is essential for PCEP-style questions.

Answer

a > b and b < 0

Answer

not (a < b)

Answer

a == b or False

Question 8

A developer writes a function that calculates the area of a rectangle and prints the result inside the function. Later, they need to use this area in another calculation. What should they do to make the function reusable and composable?

Accepted Answer

Modify the function to return the area instead of printing it.. Returning a value from a function allows the caller to capture and reuse that value in subsequent calculations, making the function composable and reusable. Printing the result inside the function (as in the original code) only outputs it to the console and discards the value, preventing further programmatic use. By modifying the function to return the area, the developer can assign the result to a variable and use it in other expressions.

Answer

Store the area in a global variable and access it later.

Answer

Keep the function as is and call it from inside another function.

Answer

Pass the area to the next calculation using a print function argument.

Question 9

Refer to the exhibit. Which of the following is true about the output?

Accepted Answer

Prints "Error: invalid literal for int() with base 10: 'abc'" then "Done". The code attempts to convert the string 'abc' to an integer using int('abc'), which raises a ValueError. The except block catches this exception and prints 'Error:' followed by the exception message, then the finally block always executes and prints 'Done'. Thus, the output is 'Error: invalid literal for int() with base 10: 'abc'' followed by 'Done'.

Answer

Prints "Error:" then "Done" without the message

Answer

Raises an unhandled exception

Answer

Prints only "Done"

Question 10

A Python program needs to store the integer value 42 in a variable named count. Which line of code correctly assigns this value?

Accepted Answer

count = 42. The assignment operator = stores a value in a variable. In this scenario, count = 42 correctly binds the name count to the integer 42. The other options either compare, reverse the assignment, or use an operator that is not valid as a standalone statement.

Answer

count == 42

Answer

42 = count

Answer

count := 42

Question 11

A developer writes the following code:

x = 5
if x > 3:
    print('A')
else:
    print('B')
print('C')

What is the output?

Accepted Answer

A
C. With x equal to 5, the condition x > 3 is True, so the if block prints 'A' and the else block is skipped. The final print('C') is outside the conditional structure and always executes. The output is therefore 'A' followed by 'C' on separate lines.

Answer

A
B
C

Answer

B
C

Answer

A

Question 12

A developer is writing a Python script that stores the number of active user sessions in a variable. They want the variable to hold the value 42 as an integer. Which of the following statements correctly assigns the integer 42 to a variable named session_count?

Accepted Answer

session_count = 42. The correct assignment uses the equals sign to bind the integer literal to the variable name. Python does not require type declarations, and the absence of quotes ensures the value is an int. The other options either create a string, use invalid syntax, or misuse an operator not intended for simple assignment.

Answer

session_count := 42

Answer

session_count = '42'

Answer

int session_count = 42

Question 13

A student runs the following code in a Python 3.11 interactive session:

>>> 7 // 2

What is displayed?

Accepted Answer

3. Floor division with the double forward slash operator divides two numbers and rounds the result down to the nearest whole number. With integer operands, Python returns an integer. Because seven divided by two is three with a remainder of one, the floor value is three, and that integer is what the interactive session displays.

Answer

3.5

Answer

1

Answer

4

Question 14

A programmer is writing a Python script to calculate the area of a circle. They write the following code:

radius = 5
area = 3.14 * radius ** 2
print(area)

What is the output of this code?

Accepted Answer

78.5. The exponentiation operator ** has higher precedence than multiplication, so radius ** 2 is computed first, yielding 25. Then 3.14 * 25 equals 78.5, which is printed. This demonstrates correct operator precedence in Python and the use of the exponentiation operator for squaring a number.

Answer

25

Answer

31.4

Answer

An error occurs because radius is an integer and cannot be used with exponentiation.

Question 15

A Python script contains the following code: x = 10 y = 3 result = x // y What is the value of result after execution?

Accepted Answer

3. The // operator performs floor division, which divides the left operand by the right and rounds down to the nearest integer. With x=10 and y=3, 10 // 3 equals 3. The other options correspond to true division, rounding up, or modulo, none of which match the behavior of //.

Answer

3.3333333333333335

Answer

1

Answer

4