PCEP Practice Test 35 — 15 Questions

Question 1

A monitoring script checks a list of sensor readings and must stop examining them as soon as a reading above 100 is found, without checking any remaining readings. The readings list contains at least one value above 100. Which loop control approach implements this behavior correctly?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Use break when a reading exceeds 100, so the loop ends immediately and no further readings are checked.. Only break exits a loop immediately when a condition is met. When a reading above 100 is encountered, break ends iteration and control moves past the loop, so no later readings are examined. The other keywords either skip one iteration, do nothing, or run after normal completion.

Answer

Use pass when a reading exceeds 100, so the loop silently ignores the condition and finishes normally.

Answer

Use continue when a reading exceeds 100, so the loop skips the rest of that iteration and keeps going.

Answer

Use else on the for loop, so the loop stops when a reading exceeds 100.

Question 2

A developer is writing a Python script and assigns a value to a variable named '2nd_place'. When the script is run, it raises a SyntaxError. What is the cause of this error?

Accepted Answer

Variable names cannot start with a digit.. Python identifiers must start with a letter or underscore, not a digit. The name '2nd_place' begins with '2', so the parser cannot treat it as a single identifier and raises a SyntaxError. Underscores are allowed, uppercase is not required, and the name is not a keyword.

Answer

Variable names must be uppercase.

Answer

The name '2nd_place' is a reserved keyword.

Answer

Variable names cannot contain underscores.

Question 3

A developer writes a function `def log_event(message, level='INFO'):` that appends a formatted string to a list. The developer calls `log_event('disk full')` and then `log_event('retrying', level='WARN')`. What is the result of these two calls?

Accepted Answer

The first call uses 'INFO' for level and the second uses 'WARN', because the default applies only when the argument is omitted.. Default arguments make a parameter optional and are bound only when the caller omits that argument. An explicit keyword argument replaces the default for that single call without changing the function's definition, so the first invocation logs at INFO and the second at WARN. Calls that mix positional and keyword arguments are valid when each parameter is filled once.

Answer

The first call raises a TypeError because a function with a default parameter must always receive that argument explicitly.

Answer

The second call raises a TypeError because positional and keyword arguments cannot be mixed in the same call.

Answer

Both calls use 'WARN', because the second call permanently changes the default for later invocations.

Question 4

A developer is writing a Python script to validate a list of usernames. The script must examine each username in the list and print 'Invalid' as soon as a username shorter than 3 characters is found, then stop checking the remaining usernames. Which control flow statement should be used inside the loop to terminate it immediately when the invalid username is encountered?

Accepted Answer

break. The break statement exits the innermost loop immediately, which is exactly what is needed to stop checking usernames once an invalid one is found. The other statements either skip only one iteration, do nothing, or exit the whole function, so they do not satisfy the requirement to terminate the loop early while continuing the rest of the script.

Answer

return

Answer

pass

Answer

continue

Question 5

A developer needs to iterate over a list named `colors` and print each color on a separate line. Which code snippet correctly accomplishes this?

Accepted Answer

for color in colors:
    print(color). The correct way to iterate over a list and print each element is to use a for loop with proper indentation and a colon at the end of the loop header. The loop variable takes each element from the list in turn, and the indented block executes for each element. This pattern is fundamental in Python for processing sequences.

Answer

for (color in colors):
    print(color)

Answer

for color in colors:
print(color)

Answer

for color in colors
    print(color)

Question 6

A cashier script stores a discount rate and a price, then computes the final amount. The developer writes:

rate = 0.15
price = 200
final = price - price * rate
print(final)

What is printed?

Accepted Answer

170.0. Python evaluates multiplication before subtraction, so price * rate is computed first as 200 * 0.15, giving 30.0. That product is then subtracted from price, yielding 170.0. Because one operand is a float, the final result is a float and is displayed with a decimal point, distinguishing it from an integer result.

Answer

30.0

Answer

200.15

Answer

170

Question 7

A data analyst maintains `matrix = [[1, 2], [3, 4], [5, 6]]` and wants a flat list `flat` containing every number in row order, that is `[1, 2, 3, 4, 5, 6]`. Which code produces this result?

Accepted Answer

flat = []
for row in matrix:
    for value in row:
        flat.append(value). Flattening a list of lists requires iterating the outer list to obtain each row and then iterating each row to reach its elements. Appending every visited integer builds the one-dimensional result in the original order. Appending whole rows keeps the nesting, hard-coded concatenation does not adapt to different sizes, and selecting a single column index drops data.

Answer

flat = []
for row in matrix:
    flat.append(row)

Answer

flat = matrix[0] + matrix[1] + matrix[2]

Answer

flat = []
for i in range(len(matrix)):
    flat.append(matrix[i][0])

Question 8

A Python developer is writing a program that prompts the user to enter a positive integer. The program should repeatedly ask for input until the user enters a number greater than zero. Which loop construct is most appropriate to implement this requirement?

Accepted Answer

while loop with a condition. The requirement is to repeatedly prompt the user until a positive integer is entered. This calls for a loop that continues based on a condition that depends on user input. A while loop is designed for such indefinite iteration, as it checks the condition before each iteration and can be controlled by the input value. Other constructs either cannot repeat indefinitely or do not exist in Python.

Answer

for loop with a range

Answer

if statement with a break

Answer

do-while loop

Question 9

A payroll script calls `calculate_bonus(employee_id, base)` inside a try block. The function raises a custom exception `BonusError` when the employee is not eligible, and the script wants to log that specific failure while still letting an unexpected ZeroDivisionError propagate to a global handler. Which except clause should the developer write?

Accepted Answer

except BonusError as err:. Naming a single specific exception type in an except clause handles exactly that failure and lets everything else propagate. Binding it with as captures the instance for logging without broadening the catch. Catching a base class or listing unrelated types would either swallow unexpected errors or fail syntactically, defeating the script's escalation requirement.

Answer

except BonusError or ZeroDivisionError as err:

Answer

except BonusError, ZeroDivisionError as err:

Answer

except Exception as err:

Question 10

A developer wants to store a collection of unique employee IDs that will be checked frequently for membership. Duplicate IDs must be automatically ignored, and the order of IDs does not matter. Which built-in data type best fits this requirement?

Accepted Answer

set. The set type is designed for unordered collections of unique hashable elements. Adding an existing employee ID leaves the set unchanged, and the in operator performs an average constant-time membership test thanks to hashing. Since the order of IDs is irrelevant and duplicates must be eliminated automatically, a set matches the described requirements more directly than any ordered sequence or key-value mapping.

Answer

dict

Answer

list

Answer

tuple

Question 11

A Python programmer is working with a list of strings called words. The programmer wants to create a new list that contains the lengths of each word, but only for words that have more than three characters. Which code snippet correctly produces this list?

Accepted Answer

lengths = [len(word) for word in words if len(word) > 3]. The correct snippet must filter words with more than three characters and then transform each remaining word into its length. The list comprehension that uses len(word) in the expression and filters with len(word) > 3 accomplishes both steps correctly. Other options either compare the wrong types, return the wrong data, or incorrectly append both words and lengths.

Answer

lengths = []
for word in words:
    if len(word) > 3:
        lengths.append(word)
    lengths.append(len(word))

Answer

lengths = [word for word in words if len(word) > 3]

Answer

lengths = [len(word) for word in words if word > 3]

Question 12

A student writes the following code:

name = "Alice"
age = 25
print("Name: " + name + ", Age: " + age)

What happens when the code runs?

Accepted Answer

A TypeError is raised because you cannot concatenate a string and an integer.. In Python, the + operator cannot combine a string and an integer. The expression attempts to concatenate the string literal with the integer variable age, which raises a TypeError. To fix this, the integer must be converted to a string using str(age) or formatted using an f-string or the format() method.

Answer

It raises a SyntaxError before execution.

Answer

It prints: Name: Alice, Age: age

Answer

It prints: Name: Alice, Age: 25

Question 13

A developer writes the following code to sum a list of scores:

scores = [12, 7, 25, 18]
total = 0
for s in scores:
    total += s
print(total)

What is printed?

Accepted Answer

62. The for loop visits every item in the scores list, and the augmented assignment total += s adds each score to the running sum. Starting from zero, the additions produce 12, 19, 44, and finally 62, which is the value printed after the loop completes.

Answer

[12, 7, 25, 18]

Answer

12

Answer

0

Question 14

A Python developer is writing a script to process a list of order IDs. The script must skip any order ID that is an empty string and continue processing the remaining IDs. Inside a `for` loop over the list, which statement should be used to skip the current iteration when an empty string is encountered and proceed with the next order ID?

Accepted Answer

continue. The `continue` statement abandons the current iteration and proceeds with the next element, which is the correct behavior for skipping empty order IDs while still processing the rest of the list. `break` would stop the loop entirely, `pass` does nothing, and `exit` would terminate the interpreter, so none of those match the filtering requirement.

Answer

pass

Answer

exit

Answer

break

Question 15

A developer wants to create a dictionary that maps employee IDs to their department names. The IDs are integers, and departments are strings. Which of the following correctly creates such a dictionary?

Accepted Answer

employees = {101: "HR", 102: "IT"}. The dictionary literal {101: "HR", 102: "IT"} is the correct syntax for creating a dictionary with integer keys and string values. The dict() constructor can also be used, but keyword arguments cannot have integer names, and passing multiple positional arguments is invalid. The literal syntax is straightforward and commonly used for this purpose.

Answer

employees = dict(101: "HR", 102: "IT")

Answer

employees = dict(101="HR", 102="IT")

Answer

employees = dict([101, "HR"], [102, "IT"])