Hackerrank - HackerRank Python Scalar Types and Operators Questions and Answers

Question 1

What is the output of the following Python code snippet?

x = 15
y = 4

result = x // y + (x % y)
print(result)

Accepted Answer

6

Answer

The floor division operator `//` calculates the quotient, discarding the remainder. `15 // 4` results in `3`. The modulo operator `%` calculates the remainder of the division. `15 % 4` results in `3`. The expression then becomes `3 + 3`, which equals `6`.

Question 2

Which of the following correctly describes the `None` object in Python?

Accepted Answer

It is a keyword used to signify the absence of a value and its type is `NoneType`.

Answer

In Python, `None` is a special constant that represents the absence of a value or a null value. It is not the same as `0`, `False`, or an empty string. `None` is the sole value of the `NoneType` data type, and it is immutable.

Question 3

A developer needs to ensure a function is only called if a list is not empty to avoid an `IndexError`. Which code snippet uses short-circuiting to achieve this safely?

`my_list = []`
`def process_list(data): print(data[0])`

Accepted Answer

`if my_list and process_list(my_list): pass`

Answer

The `and` operator in Python uses short-circuit evaluation. It evaluates the expression from left to right. If the first operand (`my_list`) is falsy (an empty list is falsy), it stops and does not evaluate the second operand (`process_list(my_list)`), thus preventing the `IndexError`. The other options would either still call the function or use incorrect logic.

Question 4

What is the value of the variable `z` after this code executes?

`z = 10 + 4 * 2 ** 3 / 8 - 1`

Accepted Answer

13.0

Answer

Python follows the PEMDAS/BODMAS order of operations. The exponentiation `2 ** 3` is calculated first (8). Then, multiplication and division are performed from left to right: `4 * 8` is 32, and `32 / 8` is 4.0. Finally, addition and subtraction are performed: `10 + 4.0` is 14.0, and `14.0 - 1` is 13.0.

Question 5

In Python, boolean values `True` and `False` are instances of which scalar type?

Accepted Answer

`bool`

Answer

The values `True` and `False` are literals of the `bool` data type. While they can behave like the integers `1` and `0` in arithmetic contexts, their fundamental type is `bool`.

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Hackerrank - HackerRank Python Scalar Types and Operators Questions and Answers