PCEP Control Flow, Loops, Lists and Logic Practice Test 4 — 15 Questions

Question 1

Which TWO of the following are valid ways to iterate over a list in reverse order? (Choose two.)

Accepted Answer

for item in reversed(lst):. `reversed(lst)` returns an iterator that yields elements in reverse order without modifying the original list. Option B is correct because `range(len(lst)-1, -1, -1)` generates indices from the last to the first, allowing index-based access. These are the two valid methods according to the PCEP certification.

Answer

for i in range(len(lst)):

Answer

for item in lst[-1::-1]:

Answer

for item in lst:

Question 2

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 3

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 4

What is the output of the code?

Accepted Answer

1
2. The code uses a `for` loop with `range(1, 4)` which generates the sequence 1, 2, 3. Inside the loop, `if i == 3: break` causes the loop to terminate when `i` equals 3, so the loop only prints 1 and 2 before breaking. There is no additional print statement after the loop, so the output is just `1` and `2` on separate lines.

Answer

1
2
3
Done

Answer

1
2
Done

Answer

1
2
3

Question 5

What is the output of the code?

Accepted Answer

['Positive', 'Zero', 'Negative']. The question stem does not contain any code. Without the code, it is impossible to determine the output. The explanation previously assumed a specific code snippet which is not present.

Answer

['Positive', 'Zero']

Answer

[Positive, Zero, Negative]

Answer

('Positive', 'Zero', 'Negative')

Question 6

What is the output of the code?

Accepted Answer

Alice
Check. The code iterates over the list `['Alice', 'Bob']`. For each name, if the length is less than 5, the loop continues to the next iteration without printing. 'Alice' has length 5, so the condition is false and 'Alice' is printed. 'Bob' has length 3, so the condition is true and the loop skips printing 'Bob'. After the loop ends, `print('Check')` executes, printing 'Check'. Therefore, the output is 'Alice' followed by 'Check' on separate lines. Option A correctly shows this.

Answer

Alice

Answer

Alice
Too young

Answer

Alice
Bob

Question 7

Refer to the exhibit.
What is the output?

Accepted Answer

[1, 4, 3, 8, 5]. The code iterates over the list `[1, 2, 3, 4, 5]` using indices. It only modifies elements at odd indices (index 1 and 3). For those elements, if the value is even, it multiplies by 2; if odd, it adds 2. At index 1, value 2 (even) becomes 4; at index 3, value 4 (even) becomes 8. Elements at even indices (0, 2, 4) remain unchanged: 1, 3, 5. Thus the final list is `[1, 4, 3, 8, 5]`.

Answer

[2, 5, 7, 9, 5]

Answer

[2, 4, 6, 8, 10]

Answer

[1, 2, 3, 4, 5]

Question 8

Refer to the exhibit.
What is printed?

Accepted Answer

A. The code uses a `for` loop to iterate over the list `['A', 'B', 'C']`. The `break` statement inside the loop executes when the variable `letter` equals `'A'`, immediately terminating the loop. Therefore, only `'A'` is printed before the loop ends, making option B correct.

Answer

None (error)

Answer

B

Answer

C

Question 9

Refer to the exhibit.
What is the output?

Accepted Answer

[1, 2]. The code creates a list [1,2,3] and uses slicing with start index 0 and end index 2 (exclusive), extracting elements at indices 0 and 1, which are 1 and 2. Therefore, the output is [1,2].

Answer

[1, 2, 3]

Answer

[0, 1, 2]

Answer

[2, 3]

Question 10

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 11

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 12

A company stores employee data as a list of dictionaries. Each dictionary has keys 'name' and 'age'. Which code correctly counts employees older than 30?

Accepted Answer

count = 0
for emp in employees:
    if emp['age'] > 30:
        count += 1. It uses a simple `for` loop to iterate directly over each dictionary in the `employees` list, checks if the value of the `'age'` key is greater than 30, and increments the counter accordingly. This is the most Pythonic and readable approach for counting elements that satisfy a condition.

Answer

count = 0
for i in range(len(employees)):
    if employees[i]['age'] <= 30:
        count += 1

Answer

count = 0
i = 0
while i < len(employees):
    if employees[i]['age'] > 30:
        count += 1

Answer

count = [emp for emp in employees if emp['age'] > 30]

Question 13

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 14

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 15

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()