PCEP Computer Programming and Python Fundamentals Practice Test 7 — 15 Questions

Question 1

Which THREE of the following are correct ways to create a list containing the numbers 1, 2, 3? (Choose three.)

Accepted Answer

[x for x in range(1,4)]. Option A, `[x for x in range(1,4)]`, is correct because a list comprehension over `range(1,4)` iterates x = 1, 2, 3 (the stop value 4 is exclusive) and builds a list `[1, 2, 3]`. Option C, `list((1, 2, 3))`, is correct because the `list()` constructor converts the tuple `(1, 2, 3)` into a new list containing those same elements. Option D, `[1, 2, 3]`, is correct because it is a direct list literal that already contains the numbers 1, 2, and 3. Option B, `(1, 2, 3)`, does not belong because parentheses create a tuple, not a list. Option E, `{1, 2, 3}`, does not belong because curly braces create a set, which is unordered and not a list.

Answer

(1, 2, 3)

Answer

{1, 2, 3}

Question 2

Which TWO of the following expressions evaluate to True? (Choose two.)

Accepted Answer

3 == 3. Option C (3 == 3) is correct because the equality operator compares the two integer literals 3 and 3, which are identical values, so the expression evaluates to True. Option E (not False) is correct because the logical not operator inverts the Boolean value False, yielding True. Option A ('a' > 'b') is incorrect because string comparison uses lexicographic ordering by character code point, and 'a' (97) is less than 'b' (98), so the expression is False. Option B (5 > 10) is incorrect because 5 is not greater than 10, so it evaluates to False. Option D (bool(0)) is incorrect because 0 is a falsy value in Python, so bool(0) returns False.

Answer

'a' > 'b'

Answer

5 > 10

Answer

bool(0)

Question 3

A developer runs the code from the exhibit and gets the error shown. Which of the following is the most likely cause?

Accepted Answer

The variable 'result' was never assigned a value.. The error message indicates that the variable 'result' is referenced before it has been assigned any value. In Python, using a variable that has never been assigned raises a NameError. The code attempts to print 'result', but no assignment to 'result' exists in the provided code, so Python cannot resolve the name.

Answer

There is a typo in the variable name.

Answer

The print function requires an import.

Answer

The variable 'result' is a string, not an integer.

Question 4

The exhibit shows a JSON configuration. Which Python data structure is best suited to represent this configuration?

Accepted Answer

Dictionary. JSON objects map directly to Python dictionaries. Option B (Tuple) is wrong because tuples are immutable and lack key-value mapping. Option C (String) is wrong because a string would lose all structure, making access by key impossible. Option D (List) is wrong because lists are ordered sequences accessed by index, not by key-value pairs.

Answer

Tuple

Answer

String

Answer

List

Question 5

A junior developer writes the following code to swap two variables: a = 5; b = 10; a = b; b = a. When they print a and b, what is the output?

Accepted Answer

10 10. After `a = b`, both variables hold the value 10. Then `b = a` assigns the current value of `a` (which is now 10) to `b`, so both remain 10. The original value of `a` (5) is lost because it was overwritten before being saved.

Answer

5 5

Answer

5 10

Answer

10 5

Question 6

A team is developing a script that processes user input. They want to ensure that if the user enters a non-numeric value when asked for age, the program does not crash. Which approach should they use?

Accepted Answer

Use int(input()) within a try-except block. Wrapping `int(input())` in a `try-except` block catches the `ValueError` that occurs when `int()` receives a non-numeric string. This prevents the program from crashing and allows graceful handling of invalid input, which is the standard Pythonic approach for robust user input validation.

Answer

Use raw_input() and then int()

Answer

Use input() with a type check after input

Answer

Use a while loop to check if input.isdigit()

Question 7

A Python script processes a large file and runs out of memory. Which solution is most appropriate?

Accepted Answer

Process the file line by line using a for loop. Reading a file line by line with a for loop in Python processes one line at a time, keeping only the current line in memory. This avoids loading the entire file into RAM, which is the root cause of the memory exhaustion when dealing with large files.

Answer

Increase the memory allocation

Answer

Use a while loop to read chunks

Answer

Read the entire file into memory and split

Question 8

A programmer wants to iterate over a list and also access the index. Which built-in function should they use?

Accepted Answer

enumerate(). The `enumerate()` function is the correct choice because it returns an iterator that yields pairs of (index, element) for each item in an iterable, allowing direct access to both the index and the value during iteration without manually managing a counter.

Answer

zip()

Answer

map()

Answer

range()

Question 9

What is the output of the following code? x = [1, 2, 3]; y = x; y.append(4); print(x)

Accepted Answer

[1,2,3,4]. In Python, variables hold references to objects, not copies. When `y = x` is executed, both `x` and `y` point to the same list object in memory. The `y.append(4)` method modifies that shared list in-place, so printing `x` reflects the change and outputs `[1, 2, 3, 4]`.

Answer

Error

Answer

[4]

Answer

[1,2,3]

Question 10

Which of the following is an immutable data type in Python?

Accepted Answer

tuple. A tuple is immutable because once created, its elements cannot be changed, added, or removed. This is enforced by Python's internal structure: tuples are stored as a fixed-length array of object references, and no methods exist to modify them in place.

Answer

set

Answer

list

Answer

dict

Question 11

A developer writes a function that returns multiple values. How should they return these values?

Accepted Answer

return a, b. In Python, a function can return multiple values by separating them with commas in the return statement. This automatically packs them into a tuple, which is then unpacked by the caller. Option A correctly uses `return a, b`, which returns a tuple `(a, b)`, allowing the caller to assign the results to separate variables.

Answer

return a+b

Answer

return [a,b]

Answer

return a; return b

Question 12

What is the result of the expression: (1 and 0) or (not False and True)?

Accepted Answer

True. 1 and 0 evaluates to 0 (falsy). not False evaluates to True, so not False and True evaluates to True. 0 or True evaluates to True (the last truthy value).

Answer

False

Answer

0

Answer

1

Question 13

Which TWO of the following statements about Python's for loop are correct? (Choose Two)

Accepted Answer

It can iterate over any sequence. Option B is correct because Python's for loop is designed to iterate over any iterable object, including sequences such as lists, tuples, strings, and ranges, as well as non-sequence iterables like dictionaries, sets, and generators. Option D is correct because Python's for loop supports an optional else clause that executes after the loop completes normally, i.e., without encountering a break statement. Option A is incorrect because a for loop does not take a while-style boolean condition; it iterates over an iterable, whereas while loops use a condition. Option C is incorrect because a for loop over an empty iterable executes zero times, unlike a do-while construct. Option E is incorrect because Python also provides the while loop, so the for loop is not the only loop.

Answer

It can be used with a while loop condition

Answer

It always executes at least once

Answer

It is the only loop in Python

Question 14

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

Accepted Answer

[1,2,3]. Option A, [1,2,3], is correct because a list literal enclosed in square brackets directly creates a list with the elements 1, 2, and 3 in order. Option B, list(range(1,4)), is correct because range(1,4) generates the integers 1, 2, 3 (the stop value 4 is exclusive), and wrapping it in the list() constructor materializes them as a list. Option D, [x for x in range(1,4)], is correct because this list comprehension iterates over range(1,4), producing the values 1, 2, 3 and collecting them into a new list. Option C, (1,2,3), is not correct because parentheses create a tuple, not a list, and tuples are immutable and of a different type. Option E, {1,2,3}, is not correct because curly braces create a set, which is unordered and contains no duplicates, so it is not a list.

Answer

(1,2,3)

Answer

{1,2,3}

Question 15

Refer to the exhibit. What is the most likely cause of this error?

Accepted Answer

Variable x is used before assignment. The error message indicates that variable 'x' is being referenced before it has been assigned a value. In Python, using a variable that has not been defined yet raises a NameError. Option B correctly identifies this as the cause.

Answer

Variable x is a string

Answer

Variable x is an integer

Answer

Variable x is misspelled