PCEP Control Flow, Loops, Lists and Logic Practice Test 6 — 15 Questions

Question 1

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 2

A developer is troubleshooting a loop that terminates earlier than expected. The code is: i = 0; while i < 5: if i == 3: break; print(i); i += 1. What is the output?

Accepted Answer

0 1 2. The loop starts with i=0 and increments i by 1 each iteration. When i reaches 3, the break statement executes, immediately terminating the loop. Therefore, only i values 0, 1, and 2 are printed, making option D correct.

Answer

0 1 2 3 4

Answer

0 1 2 3

Answer

0 1

Question 3

A developer writes a recursive function to compute factorial, but it causes a RecursionError. Which of the following is the most likely cause?

Accepted Answer

The function lacks a base case to stop recursion. A recursive function must have a base case that stops further recursive calls. Without it, the function calls itself indefinitely until the recursion limit is exceeded, raising a RecursionError. In Python, the default recursion limit is 1000, and exceeding it triggers this error.

Answer

The function returns a string instead of an integer

Answer

The function modifies a global variable incorrectly

Answer

The function uses too many parameters

Question 4

Which THREE statements about the break statement in Python are correct? (Choose three.)

Accepted Answer

It exits the innermost loop when executed.. The break statement, when executed inside a loop, immediately terminates the innermost loop it resides in, transferring control to the next statement after the loop. This is a fundamental behavior defined in Python's control flow documentation.

Answer

It can be used with an optional else clause.

Answer

It can be used in an if statement outside any loop.

Question 5

Which TWO of the following code snippets will produce the output '0 1 2'? (Choose two.)

Accepted Answer

for i in range(5): if i>2: break; print(i). The loop iterates over range(5) (0,1,2,3,4), but the break statement executes when i > 2, so the loop terminates after printing 0, 1, and 2. Option D is correct because range(3) generates exactly the sequence 0, 1, 2, and each value is printed in order.

Answer

for i in range(5): if i%2==0: print(i); else: continue

Answer

i=0; while i<3: print(i); i+=1; else: print('done')

Answer

i=0; while i<3: print(i)

Question 6

How many times will the following loop print 'Hi'?

for i in range(3):
    print('Hi')

Accepted Answer

3. The loop `for i in range(3):` iterates exactly three times because `range(3)` generates the sequence 0, 1, 2. Each iteration executes `print('Hi')`, so 'Hi' is printed three times. Option B is correct.

Answer

2

Answer

0

Answer

4

Question 7

Which loop is more efficient for iterating over a large list when you only need the values, not indices?

Accepted Answer

for value in mylist:. Iterating directly over the list with `for value in mylist:` avoids the overhead of indexing or enumeration. This is the most efficient approach in Python for accessing only the values, as it uses the list's internal iterator, which is implemented in C and involves no function calls or index lookups per iteration.

Answer

for i in range(len(mylist)): value = mylist[i]

Answer

for i, value in enumerate(mylist):

Answer

for value in mylist[::-1]:

Question 8

A program reverses a string using a while loop. The code is:

text = "hello"
reversed_text = ""
index = len(text) - 1
while index > 0:
    reversed_text += text[index]
    index -= 1
print(reversed_text)

It prints 'olle' instead of 'olleh'. What is the error?

Accepted Answer

Change the condition to 'while index >= 0:'. The while loop condition `index > 0` stops when `index` becomes 0, so the character at index 0 (the first character 'h') is never appended to `reversed_text`. Changing the condition to `while index >= 0:` ensures the loop runs for index values from 4 down to 0 inclusive, producing the full reversed string 'olleh'.

Answer

Change the initial index to len(text)

Answer

Use a for loop instead

Answer

Use string slicing: reversed_text = text[::-1]

Question 9

A student grades system:

score = 85
if score >= 90:
    grade = 'A'
elif score >= 80:
    grade = 'B'
elif score >= 70:
    grade = 'C'
else:
    grade = 'F'

What grade is assigned?

Accepted Answer

B. The code uses a cascading if-elif-else structure. Since score is 85, the first condition (score >= 90) is False, so it moves to the elif score >= 80 condition, which is True, assigning grade = 'B'. The remaining elif and else are skipped, making 'B' the correct grade.

Answer

C

Answer

A

Answer

F

Question 10

Which list method modifies the list in place by adding all elements of another iterable to the end?

Accepted Answer

extend(). The `extend()` method modifies the list in place by appending all elements from the provided iterable (e.g., another list, tuple, or string) to the end. It does not return a new list; it mutates the original list directly, which is the behavior described in the question.

Answer

+ operator

Answer

insert()

Answer

append()

Question 11

A program uses a while loop to find the largest number in a list until a negative number is encountered. What is wrong with this code?

numbers = [3, 7, 2, -1, 5]
max_num = 0
i = 0
while numbers[i] >= 0:
    if numbers[i] > max_num:
        max_num = numbers[i]
    i += 1
print(max_num)

Accepted Answer

The loop should continue even when number is negative (skip negatives).. The while loop condition `numbers[i] >= 0` causes the loop to terminate as soon as it encounters a negative number (-1), so it never processes the number 5 at the end of the list. The intended behavior is to skip negative numbers and continue iterating through the entire list to find the largest number among all non-negative values. To fix this, the loop should use a condition that checks the index against the list length (e.g., `i < len(numbers)`) and then skip negative numbers with an `if` statement inside the loop.

Answer

The loop should start with max_num = None.

Answer

The loop should check all numbers until end of list.

Answer

The loop should use a for loop instead.

Question 12

A developer wants to generate a list of squares of integers from 1 to 10 inclusive. Which list comprehension is correct?

Accepted Answer

[x**2 for x in range(1, 11)]. `range(1, 11)` generates integers from 1 to 10 inclusive, and the list comprehension `[x**2 for x in range(1, 11)]` squares each integer, producing the desired list of squares. The `range()` function's stop value is exclusive, so `range(1, 11)` stops at 10, covering all numbers from 1 to 10.

Answer

[x**2 for x in range(11)]

Answer

[x**2 for x in range(10)]

Answer

[x**2 for x in range(1, 10)]

Question 13

A developer needs to check if all elements in a list of integers are even. Which code correctly implements this?

Accepted Answer

all_even = True
for num in mylist:
    if num % 2 != 0:
        all_even = False
        break. It initializes `all_even` to `True`, then iterates through the list. If any element is odd (`num % 2 != 0`), it sets `all_even` to `False` and breaks out of the loop early, which is an efficient and correct way to check that all elements are even.

Answer

all_even = all(num % 2 for num in mylist)

Answer

all_even = any(num % 2 == 0 for num in mylist)

Answer

all_even = False
for num in mylist:
    if num % 2 == 0:
        all_even = True
    else:
        all_even = False

Question 14

Which TWO of the following list operations modify the list in place?

Accepted Answer

mylist.sort(). `mylist.sort()` sorts the list in place, meaning it modifies the original list object without creating a new one. Option E is correct because `mylist.append(5)` adds the element 5 to the end of the list, directly mutating the original list object.

Answer

mylist + [5]

Answer

mylist.copy()

Answer

mylist = mylist + [5]

Question 15

Which TWO of the following are true about Python's if statement?

Accepted Answer

An if statement can have multiple elif blocks.. Python's if statement allows multiple elif blocks to check additional conditions after the initial if condition. This enables a chain of conditional checks, and each elif is evaluated only if all previous conditions were False. The elif clause is a contraction of 'else if' and is a unique feature of Python's syntax.

Answer

if statements cannot be nested.

Answer

An if statement must have a corresponding else clause.

Answer

The condition must be enclosed in parentheses.