PCEP Data Types, Variables, Basic I/O and Operators — 50 Questions

Question 1

A developer runs the script and enters 'Alice' and '25'. What does it print?

Accepted Answer

Alice is 25 years old.. The input() function returns strings. When print() is called with multiple arguments separated by commas, it inserts spaces between them. Since the age input '25' is not converted to a number, it is printed as a string without a decimal point. Thus, the output is 'Alice is 25 years old.'

Answer

Alice is 25.0 years old.

Answer

Alice is  Alice  is 25 years old.

Answer

Alice is 25 years old. (with age as integer)

Question 2

Given the exhibit, what does the code print?

Accepted Answer

3.0. The code likely performs floor division with at least one float operand (e.g., print(7.0 // 2) or print(7 // 2.0)). Floor division // returns the largest integer less than or equal to the quotient, but if either operand is a float, the result is a float. Since 7.0 // 2 = 3.0, the output is 3.0. If both operands were integers, the result would be the integer 3, not 3.0. Thus option A (3.0) is correct.

Answer

3

Answer

3.5

Answer

3.5

Question 3

A company runs a Python script on a server that monitors network traffic. The script reads a configuration file containing a threshold value as a string, e.g., '0.85'. The script compares this threshold to a calculated load average (float). The developer writes: threshold = config['threshold']; if load > threshold: alert(). The alert never triggers even when load exceeds 0.85. The config file is correctly parsed. What is the most likely cause and solution?

Accepted Answer

The threshold is a string; convert it to float before comparison.. The configuration file stores the threshold as a string ('0.85'), but in Python 3, comparing a float to a string raises a TypeError, not a silent failure. The script may have a try-except block that catches this, or it crashes. The developer must explicitly convert the threshold to a float using float(config['threshold']) before the comparison.

Answer

The config file key is misspelled; check spelling.

Answer

Use a try-except block to catch TypeError.

Answer

The load variable is a string; convert to float.

Question 4

Refer to the exhibit. What is the printed value?

Accepted Answer

35. The expression in the exhibit is (2+3)*(5+2). Parentheses have the highest precedence, so we first evaluate the two addition operations: 2+3=5 and 5+2=7. Then we multiply the results: 5*7=35. Therefore, the printed value is 35, corresponding to option D.

Answer

27

Answer

5

Answer

21

Question 5

A developer needs to swap the values of two variables a and b without using a temporary variable. Which single line of code correctly performs the swap?

Accepted Answer

a, b = b, a. Python supports tuple unpacking, which allows swapping the values of two variables in a single line without a temporary variable. The expression `a, b = b, a` evaluates the right-hand side tuple `(b, a)` first, then assigns the values to `a` and `b` respectively, effectively swapping them. Option A fails because after `a = b`, the original value of `a` is lost, so `b = a` assigns the same value to both. Option C (XOR swap) works but requires three statements, not a single line. Option D (arithmetic swap) also works but requires three statements and may cause overflow in other languages, though Python handles big integers; still, it is not a single line.

Answer

a = b; b = a

Answer

a = a ^ b; b = a ^ b; a = a ^ b

Answer

a = a + b; b = a - b; a = a - b

Question 6

A developer is working on a project that requires handling large numbers. They write:

x = 10000000000
y = 3.0
z = x / y
print(int(z))

The output is 3333333333. However, the developer expected 3333333333 (same). But they suspect that integer division might be better. They try:

x = 10000000000
y = 3
z = x // y
print(z)

Output: 3333333333. Both give same. Now they test with negative numbers:

x = -10
y = 3
z1 = x / y
z2 = x // y
print(z1, z2)

The output is -3.3333333333333335 and -4. The developer is confused why z2 is -4 instead of -3. Which of the following explains the behavior?

Accepted Answer

Floor division always rounds down toward negative infinity, so -10 // 3 = -4 because -3.33 floor is -4.. Python's floor division (`//`) always rounds down toward negative infinity, not toward zero. For `-10 // 3`, the exact result is approximately -3.333, and the floor (largest integer ≤ the value) is -4, not -3. This is consistent with the mathematical definition of floor division used in Python. Option B is incorrect because Python's `//` is not truncation; it is floor division, and Python does not have a bug. Options A and D also misstate the behavior.

Answer

The division operator / rounds toward zero, while // rounds toward negative infinity.

Answer

Truncation division always rounds toward zero, so -10 // 3 should be -3, but Python has a bug.

Answer

The result depends on the types; using float y yields different result.

Question 7

A developer writes the following code: x = 5; y = 2; print(x // y). What is the output?

Accepted Answer

2. The floor division operator (//) in Python returns the largest integer less than or equal to the result of the division. Since 5 divided by 2 equals 2.5, the floor is 2, and the result is an integer (int) because both operands are integers. Therefore, the output is 2.

Answer

1

Answer

2.0

Answer

2.5

Question 8

A junior developer writes: x = 10; y = 3; print(x % y). What will be printed?

Accepted Answer

1. The modulo operator (%) returns the remainder of the division of the left operand by the right operand. Here, 10 divided by 3 equals 3 with a remainder of 1, so print(x % y) outputs 1.

Answer

3.33

Answer

0

Answer

3

Question 9

A developer needs to convert a string '25' to an integer and then add 10. Which code correctly performs this?

Accepted Answer

print(int('25') + 10). `int('25')` converts the string '25' to the integer 25, and then `+ 10` performs integer addition, resulting in 35. The `print()` function outputs the result. This follows Python's type conversion rules where explicit conversion is required to combine a string and an integer in arithmetic.

Answer

print('25' + 10)

Answer

print(int('25') + '10')

Answer

print('25' + str(10))

Question 10

What is the correct way to read a floating-point number from user input and store it in a variable?

Accepted Answer

x = float(input()). `float(input())` first reads the user input as a string via `input()`, then converts that string to a floating-point number using the `float()` function. This is the standard and only valid way in Python to obtain a float from console input, as `input()` always returns a string.

Answer

x = input(float())

Answer

x = input() as float

Answer

x = input().float()

Question 11

A developer wants to assign the value 3.14 to a variable and later change it to the integer 3. Which of the following is true?

Accepted Answer

This is allowed because Python is dynamically typed.. Python is dynamically typed, meaning variables can be reassigned to values of any type at runtime. The developer can first assign the float 3.14 to a variable and later reassign the integer 3 to the same variable without any type declaration or conversion function required.

Answer

This is allowed only if the variable was declared as a float.

Answer

This causes a TypeError because you cannot change types.

Answer

This is allowed only if you use the int() function during assignment.

Question 12

Which of the following is a valid variable name in Python?

Accepted Answer

_count. (_count) is correct because in Python, variable names can start with an underscore, and underscores are allowed anywhere in the name. The name _count follows all Python identifier rules: it starts with a letter or underscore, contains only letters, digits, or underscores, and is not a reserved keyword.

Answer

my-var

Answer

2nd_place

Answer

class

Question 13

A developer writes: print(10 * '5'). What is the output?

Accepted Answer

5555555555. In Python, the multiplication operator (*) when used with a string and an integer performs string repetition. The expression 10 * '5' repeats the string '5' ten times, resulting in the string '5555555555'. The print() function then outputs this concatenated string without quotes.

Answer

10

Answer

50

Answer

5

Question 14

What is the result of the expression: print(2 ** 3 ** 2) ?

Accepted Answer

512. The expression `2 ** 3 ** 2` uses the exponentiation operator `**`, which in Python is right-associative. This means it is evaluated as `2 ** (3 ** 2)`, not `(2 ** 3) ** 2`. First, `3 ** 2` equals 9, then `2 ** 9` equals 512. Therefore, option A is correct.

Answer

256

Answer

64

Answer

128

Question 15

A beginner writes: x = '10'; y = 20; print(x + y). What happens?

Accepted Answer

Raises TypeError. Python's type system does not allow implicit concatenation of a string and an integer. The variable `x` is a string (`'10'`), and `y` is an integer (`20`). The `+` operator with these types triggers a `TypeError: unsupported operand type(s) for +: 'int' and 'str'` (or vice versa), as Python refuses to guess the programmer's intent.

Answer

Prints 30

Answer

Prints 10 + 20

Answer

Prints 1020

Question 16

Which operator is used to check if two values are equal in Python?

Accepted Answer

==. The == operator is Python's equality comparison operator, used to check if two values are equal. It returns True if the values are equal and False otherwise, making it the standard way to test equality in conditions and expressions.

Answer

=

Answer

eq

Answer

!=

Question 17

A developer writes: a = 3; b = 4; c = a + b / 2. What is the value of c?

Accepted Answer

5.0. In Python, the division operator `/` always returns a float, and operator precedence dictates that division is performed before addition. Thus, `b / 2` evaluates to `4 / 2 = 2.0`, then `a + 2.0` yields `3 + 2.0 = 5.0`. Option D is correct because the result is a float value of 5.0.

Answer

3

Answer

3.5

Answer

5

Question 18

Which TWO of the following are valid ways to create a variable with the integer value 100?

Accepted Answer

x = int('100'). The `int()` function converts a string containing a valid integer literal, such as '100', into an integer value of 100. This is a standard type-casting operation in Python that explicitly creates an integer from a string representation.

Answer

x = 0100

Answer

x = 100.0

Answer

x = '100'

Question 19

Which THREE of the following expressions evaluate to True?

Accepted Answer

3 == 3. The equality operator '==' compares the integer values 3 and 3, which are identical, so the expression evaluates to True. In Python, '==' checks for value equality, not identity, and since both operands are the same integer literal, the result is True.

Answer

1 < 0

Answer

4 > 5

Question 20

Which TWO of the following are valid Python data types?

Accepted Answer

str. (str) is correct because Python uses 'str' as its built-in type for textual data, which is a sequence of Unicode characters. This is a fundamental data type in Python, distinct from other languages that might use 'string' or 'char'.

Answer

real

Answer

array

Answer

char