PCEP Practice Test 16 — 15 Questions

Question 1

A junior developer is writing a script to read a number from input and double it. They write:

num = input("Enter a number: ")
result = num * 2
print(result)

When they test with input 5, the output is '55' instead of 10. What is wrong?

Accepted Answer

The input is treated as a string; they need to convert it to int.. Option A is correct because input returns a string, and multiplying a string repeats it. Option B is wrong because there is no syntax error. Option C is wrong because the logic is correct if the input is numeric, but the type is wrong. Option D is wrong because print does not cause this behavior.

Answer

There is a syntax error in the multiplication line.

Answer

The print function is incorrectly formatting the output.

Answer

The variable name 'num' conflicts with a built-in function.

Question 2

Which of the following code snippets will correctly assign the integer 10 to the variable 'x'?

Accepted Answer

x = 10. Option A is correct because it uses the assignment operator '=' to assign the integer 10. Option B is wrong because '==' is a comparison operator. Option C is wrong because the variable name cannot start with a number. Option D is wrong because the syntax is reversed.

Answer

x == 10

Answer

x := 10

Answer

10 = x

Question 3

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)]. Options A, B, and D are correct. Option A uses square brackets. Option B uses the list() constructor with a tuple. Option D uses a generator expression converted to list. Option C is wrong because (1,2,3) is a tuple, not a list. Option E is wrong because it creates a set.

Answer

(1, 2, 3)

Answer

{1, 2, 3}

Question 4

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]. Assignment y = x creates a reference to the same list object, not a copy. Modifying y also modifies x. Therefore, x becomes [1,2,3,4].

Answer

Error

Answer

[4]

Answer

[1,2,3]

Question 5

A developer wrote: a, b, c = 10, 20, 30; avg = a + b + c / 3; print(avg). What is the output?

Accepted Answer

40.0. Division has higher precedence than addition, so c/3 = 10, then a+b+10 = 40.0. Option C is correct.

Answer

60.0

Answer

20.0

Answer

30.0

Question 6

Refer to the exhibit. What is the output?

Accepted Answer

[1, 4, 3, 16, 5]. The loop iterates over indices. For even values (2,4), they are squared: 2->4, 4->16. Others unchanged. Result: [1,4,3,16,5]. Option C is correct.

Answer

[1, 2, 3, 4, 5]

Answer

[1, 2, 9, 4, 25]

Answer

[1, 4, 9, 16, 25]

Question 7

A developer is writing a script to process user input. The script should repeatedly ask for a number until a valid integer is entered. Which loop structure is most appropriate?

Accepted Answer

while loop with a condition. A while loop with a condition that checks if the input is valid is the standard approach for input validation.

Answer

for loop

Answer

do-while loop

Answer

Recursion

Question 8

Which of the following variable names is valid in Python?

Accepted Answer

_private. Option C is correct because variable names can start with an underscore. Option A is wrong because it starts with a digit. Option B is wrong because 'my-var' contains a hyphen. Option D is wrong because 'class' is a reserved keyword.

Answer

1st_value

Answer

class

Answer

my-var

Question 9

Which TWO of the following code snippets will produce the output 'True'? (Assume all variables are defined appropriately.)

Accepted Answer

print(3.0 == int(3.0)). Correct options are B and D. B: 'is' checks identity, and a and b point to same small integer due to caching. D: 3.0 == 3 returns True due to type coercion. A: 'is' with different float objects returns False. C: 1 <= 2 <= 3 is chained comparison: 1<=2 and 2<=3 -> True and True -> True, but that's actually True? Wait 1 <= 2 <= 3 is True. But we need TWO correct. Let me recalc: A) x=2.0; y=2.0; print(x is y) -> may be False because floats are not small ints; typically False. B) a=5; b=5; print(a is b) -> True due to integer caching. C) print(1 <= 2 <= 3) -> True. D) print(3.0 == 3) -> True. E) print('ab' == 'ba') -> False. So three options give True? That's three correct, but we need exactly two. So adjust: make C False? For example, print(1 <= 2 <= 1) -> False. Or change to something else. Let me redesign: A) print(2.0 is 2.0) -> probably False (no small float cache). B) a=256; b=256; print(a is b) -> True (integers -5 to 256 cached). C) print(1 < 2 < 3) -> True. D) print(3.0 == int(3.0)) -> True. E) print('abc' == 'abc') -> True. That's three. So to have exactly two, we need to make one of these false. For C, change to 1 < 2 < 1 -> False. For D, change to 3.0 == 3 -> still True. For E, change to 'ab' == 'ba' -> False. So then only B and D are True. That works. But careful: int(3.0) is 3, so True. So final snippet: A) x=2.0; y=2.0; print(x is y) -> False. B) a=256; b=256; print(a is b) -> True. C) print(1 < 2 < 1) -> False. D) print(3.0 == int(3.0)) -> True. E) print('ab' == 'ba') -> False. Thus correct: B and D.

Answer

x=2.0; y=2.0; print(x is y)

Answer

print(1 < 2 < 1)

Answer

print('ab' == 'ba')

Question 10

Which TWO of the following are valid variable names in Python? (Choose two.)

Accepted Answer

my_var_2. Option A is incorrect because variable names cannot start with a digit. Option B is incorrect because 'for' is a reserved keyword. Option C is correct: underscores are allowed. Option D is correct: names can start with underscore. Option E is incorrect because '@' is not allowed in identifiers.

Answer

1st_value

Answer

user@name

Answer

for

Question 11

Which TWO of the following are valid variable names in Python?

Accepted Answer

_myVar. Variable names must start with a letter or underscore, and cannot contain hyphens or start with a digit. '2ndPlace' starts with a digit, 'my-var' contains a hyphen. Valid ones are '_myVar' and 'my_var'.

Answer

myVar

Answer

my-var

Answer

2ndPlace

Question 12

According to PEP 8, which of the following is the recommended way to name a constant representing the maximum number of retries?

Accepted Answer

MAX_RETRIES. Option D is correct because constants are typically named in uppercase with underscores. Option A is wrong because it uses camelCase which is not recommended for constants. Option B is wrong because it uses lowercase with spaces. Option C is wrong because it starts with a number.

Answer

max_retries

Answer

1st_retry_limit

Answer

maxRetries

Question 13

What is the output of the code in the exhibit?

Accepted Answer

Greater. Option B is correct because x=10 is greater than 5, so the if branch executes, printing 'Greater'. Option A is wrong because the condition is true. Option C is wrong because both prints are not executed. Option D is wrong because there is no syntax error.

Answer

Greater
Less or equal

Answer

SyntaxError

Answer

Less or equal

Question 14

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

Accepted Answer

return a, b. In Python, returning multiple values separated by commas automatically packs them into a tuple, which is the standard way.

Answer

return a+b

Answer

return [a,b]

Answer

return a; return b

Question 15

A programmer needs to read a file line by line and process each line. Which of the following is the most memory-efficient and Pythonic approach?

Accepted Answer

with open('file.txt') as f: for line in f: print(line). Using a for loop on the file object iterates lazily without loading the entire file into memory. Option D is correct.

Answer

lines = open('file.txt').read().split('
')

Answer

content = open('file.txt').read().splitlines()

Answer

for line in open('file.txt'): print(line)