PCEP Practice Test 14 — 15 Questions

Question 1

Given x = 100 and y = 105, what is the value of z if z = x + y?

Accepted Answer

205. The values of x and y are 100 and 105 respectively. The expression z = x + y calculates their sum: 100 + 105 = 205. Therefore, print(z) outputs 205.

Answer

200

Answer

25

Answer

250

Question 2

What is the output of the following code?

numbers = [1, 2, 3, 4, 5]
total = 0
for i in numbers:
    if i % 2 == 0:
        continue
    total += i
print(total)

Accepted Answer

9. The exhibit shows code that iterates over the list [1, 2, 3, 4, 5] and uses `if i % 2 == 0: continue` to skip even numbers. Only odd numbers (1, 3, 5) are summed, giving 1 + 3 + 5 = 9. Therefore, option D is correct.

Answer

10

Answer

8

Answer

6

Question 3

Which two of the following statements about Python lists are true?

Accepted Answer

List elements can be accessed using negative indices.. Python lists support negative indexing, where -1 refers to the last element, -2 to the second last, and so on. This allows convenient access to elements from the end of the list without needing to calculate the length.

Answer

Lists are immutable.

Answer

The append() method inserts an element at the beginning of the list.

Answer

Lists can only contain elements of the same data type.

Question 4

A developer writes:
try:
    x = int('hello')
except ValueError:
    x = 0
except TypeError:
    x = -1
finally:
    x = x + 1
What is the final value of x?

Accepted Answer

1. The code attempts to convert the string 'hello' to an integer, which raises a ValueError. The except ValueError block catches this and sets x = 0. The finally block always executes, adding 1 to x, so x becomes 1. The TypeError except is never triggered because the error is a ValueError, not a TypeError.

Answer

0

Answer

-1

Answer

2

Question 5

Which TWO of the following are valid ways to create a dictionary with initial key-value pairs? (Select exactly 2)

Accepted Answer

d = {'a': 1, 'b': 2}. It uses the standard literal syntax for creating a dictionary with initial key-value pairs. The curly braces `{}` with colon-separated keys and values are the most common and direct way to define a dictionary in Python.

Answer

d = ('a'=1, 'b'=2)

Answer

d = dict.fromkeys(['a', 'b', 'c']) # without value

Answer

d = dict(['a', 'b'], [1, 2])

Question 6

Which THREE of the following statements about Python exception handling are correct?

Accepted Answer

The finally block always runs.. The `finally` block in Python is guaranteed to execute regardless of whether an exception occurred, was caught, or even if the `try` block contains a `return`, `break`, or `continue` statement. This ensures cleanup actions like closing files or releasing resources always run.

Answer

You must have at least one except block if you have a finally block.

Answer

A try block must have at least one except block.

Question 7

A script uses the // operator with negative numbers. For example, -7 // 2 returns -4. The developer expected -3. Which statement best explains this behavior?

Accepted Answer

The // operator performs floor division, which rounds down to the next lower integer.. In Python, the // operator performs floor division, which always rounds down to the next lower integer (toward negative infinity). For -7 // 2, the exact result is -3.5, and floor division rounds down to -4, not -3. This behavior is defined by the Python language specification and differs from truncation toward zero.

Answer

The // operator uses banker's rounding.

Answer

The // operator truncates toward zero for negative numbers.

Answer

The // operator performs integer division with rounding to the nearest even integer.

Question 8

What does the following code output?

try:
    x = int('abc')
except ValueError:
    print('Invalid')

Accepted Answer

Invalid. The code attempts to convert the string 'abc' to an integer using int(). Since 'abc' is not a valid integer, Python raises a ValueError. The except block catches this specific exception and executes print('Invalid'), so the output is 'Invalid'. Option B is correct because the exception is handled gracefully without crashing.

Answer

The program crashes

Answer

(Nothing printed)

Answer

abc

Question 9

A developer is writing a simple number guessing game. The computer picks a random number between 1 and 100, and the user keeps guessing until correct. The developer implements:

secret = random.randint(1,100)
guess = 0
while guess != secret:
    guess = int(input("Guess: "))
    if guess == secret:
        print("Correct!")
    else:
        print("Wrong, try again.")

The game works, but the developer notices that if the user enters something that is not an integer, the program crashes. Which modification ensures the program handles non-integer input gracefully?

Accepted Answer

Use a try-except around the input conversion. Wrapping the `int(input(...))` in a `try-except` block catches the `ValueError` that occurs when the user enters a non-integer string. This allows the program to handle the error gracefully (e.g., by printing a message and continuing the loop) instead of crashing. The other options do not prevent the crash when `int()` receives invalid input.

Answer

Use a while True loop with break

Answer

Change the data type of guess to string

Answer

Add an if statement to check if input is digit

Question 10

A company uses a for loop to iterate over a list of transaction amounts. They want to skip negative amounts. Which statement inside the loop correctly achieves this?

Accepted Answer

if amount < 0: continue. The `continue` statement immediately jumps to the next iteration of the loop, skipping any remaining code in the current iteration. When `amount < 0`, the loop will not process that negative transaction and will move to the next element in the list, effectively skipping negative amounts.

Answer

if amount < 0: amounts.remove(amount)

Answer

if amount < 0: break

Answer

if amount < 0: pass

Question 11

A developer writes the following code: x = 5; y = x; x = 10. What are the values of x and y after execution?

Accepted Answer

x = 10, y = 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 = 10` is executed, it binds the name `x` to a new integer object 10, while `y` still references the original object 5. Thus, after execution, `x` is 10 and `y` is 5.

Answer

x = 5, y = 10

Answer

x = 5, y = 5

Answer

x = 10, y = 10

Question 12

Which FOUR of the following are valid ways to create a list with elements 1, 2, 3? (Choose four.)

Accepted Answer

[1, 2, 3,]. Option A, [1, 2, 3,], is correct because Python allows a trailing comma after the last element in a list literal, so it still produces the list [1, 2, 3]. Option B, list(range(1, 4)), is correct because range(1, 4) yields 1, 2, and 3 (the stop value 4 is exclusive), and list() converts that iterable into [1, 2, 3]. Option C, [1, 2, 3], is correct as the standard list literal syntax that directly creates the list [1, 2, 3]. Option E, list((1, 2, 3)), is correct because (1, 2, 3) is a tuple containing those three integers, and list() converts the tuple into the list [1, 2, 3]. Option D, list(1, 2, 3), is not valid because list() takes at most one argument (an iterable), so passing three separate integer arguments raises a TypeError.

Answer

list(1, 2, 3)

Question 13

A support technician is running a Python script that parses a configuration file and stores key-value pairs in a dictionary called 'config'. The script then uses these values to set application parameters. The configuration file is optional, and some expected keys may be missing. Currently, the script crashes with a KeyError when accessing a missing key. The technician needs to modify the script to safely retrieve a value or return 'N/A' if a key is missing. The script must remain efficient and readable. Which modification best achieves this?

Accepted Answer

Use config.get(key, 'N/A') instead of direct key access. `dict.get(key, default)` is the idiomatic Python method for safely retrieving a value from a dictionary without raising a `KeyError`. It returns the default value `'N/A'` when the key is missing, which directly solves the crash while keeping the code concise and readable. This approach is more efficient than exception handling or explicit membership checks because it performs a single hash lookup.

Answer

Wrap each access in a try-except block to catch KeyError and assign 'N/A'

Answer

Use if key in config: value = config[key] else: value = 'N/A'

Answer

Use config.setdefault(key, 'N/A') before accessing

Question 14

Given a list of names = ['Alice', 'Bob', 'Charlie'], a developer wants to create a dictionary mapping each name to its length. Which expression accomplishes this?

Accepted Answer

{name: len(name) for name in names}. It uses a dictionary comprehension that iterates over each name in the list, using the name as the key and the result of `len(name)` as the value. This directly maps each name to its length, which is exactly what the developer wants.

Answer

{len(name): name for name in names}

Answer

{name: len for name in names}

Answer

{name: length for name in names}

Question 15

You are a junior developer at a small startup. Your team has a Python script that automates daily data processing. The script reads a CSV file, processes each row, and writes results to a new file. Recently, the script started crashing with a 'ValueError: invalid literal for int()' error. The error occurs on a line that converts a field to an integer using int() on a string value. The CSV file comes from an external source that sometimes contains non-numeric values like 'N/A' or empty strings. Which course of action is best to handle this robustly without stopping the entire process?

Accepted Answer

Wrap the conversion in a try-except block and handle the exception appropriately for each row.. Wrapping the conversion in a try-except block allows the script to catch the ValueError for each row individually, log or handle the problematic row (e.g., skip it or use a default value), and continue processing the remaining rows without crashing. This is the standard Pythonic approach for handling expected but unpredictable data quality issues in external input, as it separates error handling from the main logic and preserves the robustness of the batch process.

Answer

Add logging before the conversion to print the problematic value.

Answer

Use a regex to replace all non-digit characters before conversion.

Answer

Contact the external source to ensure no missing values are sent.