PCEP Practice Test 30 — 15 Questions

Question 1

A Python programmer is analyzing a list of integers named numbers. The programmer wants to create a new list that contains only the even numbers from numbers, each multiplied by 10. Which two of the following code snippets correctly produce the desired list? (Choose two.)

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

Accepted Answer

result = []
for n in numbers:
    if n % 2 == 0:
        result.append(n * 10). The desired output requires filtering even numbers and then multiplying each by 10. The explicit for-loop with append and the list comprehension both correctly perform this filter-and-transform operation. The other options either select odd numbers, fail to multiply, or multiply the list itself instead of its elements.

Answer

result = [n * 10 for n in numbers if n % 2 != 0]

Answer

result = []
for n in numbers:
    if n % 2 == 0:
        result.append(n)
        n = n * 10

Answer

result = [n for n in numbers if n % 2 == 0] * 10

Question 2

A Python developer writes the following code to concatenate two strings:

first = 'Hello'
second = 'World'
result = first + ' ' + second
print(result)

What is the output?

Accepted Answer

Hello World. The + operator concatenates strings when both operands are strings. Here, first is 'Hello', then a space string ' ', then second is 'World'. The result is 'Hello World'. The other options either omit the space, include quotes, or predict an error that does not occur because all operands are strings.

Answer

HelloWorld

Answer

'Hello' 'World'

Answer

Error: cannot concatenate str and int

Question 3

A script starts with:

name = "Ada"
age = 36

Which line correctly prints: Ada is 36 years old

Accepted Answer

print(name, "is", age, "years old"). The print function accepts multiple arguments and inserts a space between each one, so it can mix strings and numbers without manual conversion. Concatenation with + requires both operands to be strings, so it fails when an integer is involved unless str is applied. The multi-argument form is the simplest correct way to produce the sentence.

Answer

print("name is age years old")

Answer

print(name + " is " + int(age) + " years old")

Answer

print(name + " is " + age + " years old")

Question 4

A programmer is writing a script to process a list of sensor readings. The script should stop processing as soon as a reading of 0 is encountered. Which statement should be placed inside the loop to achieve this?

Accepted Answer

break. To stop a loop immediately when a condition is met, the `break` statement is used. It transfers control to the statement immediately following the loop. The `continue` statement would only skip the current iteration, while `pass` does nothing and `exit` is not a valid loop control statement.

Answer

exit

Answer

pass

Answer

continue

Question 5

A student writes a program to classify a number:

num = 7
result = num > 5 and num < 10 or num == 0
print(result)

What is printed, and why?

Accepted Answer

True, because and has higher precedence than or, so (num > 5 and num < 10) is evaluated first and is True.. Python's logical operators follow a precedence order with and binding tighter than or, and comparison operators binding tighter than both. The expression is grouped as (num > 5 and num < 10) or (num == 0). With num = 7, the first group is True, so the entire expression short-circuits to True, and that value is printed.

Answer

True, because comparison operators are evaluated after logical operators.

Answer

False, because or is evaluated before and, making the expression False.

Answer

False, because num == 0 is False and that makes the whole expression False.

Question 6

A developer writes a script to track inventory:

apples = 15
oranges = 4
apples -= oranges
oranges += apples
print(apples, oranges)

What is printed?

Accepted Answer

11 15. Augmented assignment operators like -= and += modify the variable in place and take effect immediately. After apples -= oranges, apples is 11. The next line adds that new apples value to oranges, making oranges 15. The printed output reflects these sequential updates, so the correct pair is 11 and 15.

Answer

11 4

Answer

19 4

Answer

11 19

Question 7

A script runs:

x = 5
y = x
y += 3
print(x, y)

What is printed?

Accepted Answer

5 8. Names in Python are references to objects, and integers are immutable. Assigning y = x makes both names point to the same 5 object, but y += 3 creates a new integer and rebinds only y. Since x is never reassigned, it continues to reference 5, and the output is 5 8.

Answer

5 5

Answer

8 5

Answer

8 8

Question 8

A developer is reviewing operators in Python. Which TWO of the following statements about comparison and logical operators are correct? (Choose two.)

Accepted Answer

The expression 3 < 5 < 8 is evaluated as (3 < 5) and (5 < 8).. Python evaluates chained comparisons as a series of and-ed comparisons, evaluating the middle operand once, and its logical operators return operands rather than forcing booleans while short-circuiting. Recognizing these two behaviors explains idioms like range checks and default-value fallbacks. The other statements misstate case sensitivity of strings, short-circuit evaluation of or, and the truthiness of zero.

Answer

The expression 'a' == 'A' evaluates to True because comparisons ignore case.

Answer

The or operator always evaluates both of its operands before returning a result.

Answer

The expression not 0 evaluates to False because 0 is a number.

Question 9

A developer is writing a Python script that must iterate over the characters of the string stored in variable `word` and print each character on its own line, without using index numbers. Which of the following loops accomplishes this?

Accepted Answer

for ch in word:
    print(ch). A Python `for` loop iterates directly over any iterable object, and strings are iterables that produce their characters one at a time. Binding each character to a loop variable and printing it yields exactly one character per line in the original order. The remaining constructs either iterate over numeric indexes, never advance the loop variable, or split the string into words rather than characters.

Answer

while word:
    print(word)

Answer

for ch in word.split():
    print(ch)

Answer

for ch in range(len(word)):
    print(ch)

Question 10

A developer is writing a Python script that should keep prompting for a password until the user enters the correct one. The script must not run forever if the user never guesses correctly, so it should give up after 5 attempts. Which loop construct is most appropriate for this scenario?

Accepted Answer

A for loop that iterates over range(5), checking the password inside and breaking when correct.. The requirement combines a fixed maximum number of attempts with the possibility of stopping early on success. A for loop over range(5) supplies the exact bound of five iterations, and a break inside ends the loop as soon as the password matches. The other constructs either loop forever when the user keeps failing or do not model repeated input attempts at all.

Answer

A for loop that iterates over the characters of the password string, comparing each character.

Answer

A while True loop with no break statement, relying on the password check to terminate.

Answer

A while loop that continues as long as the entered password is incorrect, with no attempt counter.

Question 11

A logistics coordinator stores shipment weights in a list `weights = [12, 18, 7, 25]`. She needs to find the average weight of all shipments. Which code snippet correctly computes and prints the average?

Accepted Answer

print(sum(weights) / len(weights)). The average is calculated by dividing the sum of all elements by the number of elements. The built-in `sum()` and `len()` functions provide these values directly, and the `/` operator returns a float result. The other options either use incorrect functions or perform integer division, which loses the fractional part.

Answer

print(total(weights) / len(weights))

Answer

print(mean(weights) / len(weights))

Answer

print(sum(weights) // len(weights))

Question 12

A teacher writes a program that must print each student name from a list called roster on its own line, but stop printing entirely as soon as the name "STOP" is encountered, without printing "STOP" itself. Which loop body achieves this?

Accepted Answer

for name in roster:
    if name == "STOP":
        break
    print(name). Placing the sentinel comparison before the print call and using break ensures the loop terminates at the first occurrence of "STOP" without emitting that value. Checking after printing would leak the sentinel into the output, and using continue would skip only one element while later names still print, so only the pre-check with break satisfies both conditions.

Answer

for name in roster:
    while name != "STOP":
        print(name)
        break

Answer

for name in roster:
    print(name)
    if name == "STOP":
        break

Answer

for name in roster:
    if name == "STOP":
        continue
    print(name)

Question 13

A logistics analyst maintains a list `weights` representing the mass of parcels in kilograms. The analyst needs to determine how many parcels weigh more than 10 kg, but the list also contains a few `None` values that indicate missing measurements and must not be counted. Which code correctly counts only the parcels heavier than 10 kg while ignoring missing entries?

Accepted Answer

count = 0
for w in weights:
    if w is not None and w > 10:
        count += 1. The correct code uses a combined condition that first verifies the element is not None, then compares it with 10. This ordering exploits short-circuit evaluation so that None never reaches the numeric comparison. As a result, only actual numeric weights greater than 10 increment the counter, and missing measurements are silently skipped as required by the analyst.

Answer

count = 0
for w in weights:
    if w > 10:
        count += 1

Answer

count = sum(1 for w in weights if w > 10)

Answer

count = 0
for w in weights:
    if w > 10 or w is None:
        count += 1

Question 14

A developer defines a function `def add_item(item, basket=[]):` and calls it multiple times without providing a basket argument. After three calls with different items, what is the content of the default basket?

Accepted Answer

The basket contains all three items from the three calls, because the default list is shared and mutated.. Default arguments are evaluated once at function definition, so a mutable default like a list is shared across all calls that do not provide an explicit argument. The list is modified in place with each append, causing all items to accumulate. The other options incorrectly assume per-call initialization, overwriting, or a runtime error.

Answer

Each call gets a fresh empty list, so the basket remains empty after each call.

Answer

A TypeError is raised because mutable default arguments are not allowed in Python.

Answer

The basket contains only the item from the most recent call, as previous items are overwritten.

Question 15

An inventory script stores product quantities in a list named stock. The script must print the running total of quantities from the start of the list up to, but not including, the first zero quantity it encounters. Which code fragment produces this behavior?

Accepted Answer

total = 0
for q in stock:
    if q == 0:
        break
    total += q
print(total). The requirement is to accumulate quantities until the first zero appears, then stop without adding that zero. Placing the zero test before the addition and exiting with break achieves exactly this, because the loop terminates before the zero can be added to the running total.

Answer

total = 0
for q in stock:
    total += q
    if q == 0:
        break
print(total)

Answer

total = 0
for q in stock:
    if q == 0:
        continue
    total += q
print(total)

Answer

total = 0
for q in stock:
    total += q
    if q == 0:
        continue
print(total)