Understanding Python Variables and Data Types

Which function is used to take input from the user in Python?

• `print()`

• `input()`

• `read()`

• `scan()`

Answer explanation

The `input()` function is used in Python to take input from the user. It prompts the user for input and returns it as a string, making it the correct choice among the options provided.

What is the output of the following code snippet? ```python print("Hello, World!") ```

• `Hello, World!`

• `hello, world!`

• `HELLO, WORLD!`

• `Hello World`

Answer explanation

The code snippet prints the exact string "Hello, World!" to the console. Therefore, the correct output is `Hello, World!`, matching the first answer choice.

Which of the following is a mutable data type in Python?

• `tuple`

• `list`

• `str`

• `int`

Answer explanation

In Python, a `list` is a mutable data type, meaning its contents can be changed after creation. In contrast, `tuple`, `str`, and `int` are immutable, meaning their values cannot be altered once defined.

What is the correct way to declare a constant in Python?

• `PI = 3.14`

• `const PI = 3.14`

• `PI := 3.14`

• `constant PI = 3.14`

Answer explanation

The correct way to declare a constant in Python is `PI = 3.14`. Python does not have a built-in constant declaration keyword like `const` or `constant`. The convention is to use uppercase letters to indicate a constant.

Which of the following is not a valid variable name in Python?

• `my_var`

• `2ndVar`

• `var_2`

• `myVar`

Answer explanation

In Python, variable names cannot start with a digit. Therefore, `2ndVar` is not a valid variable name, while `my_var`, `var_2`, and `myVar` are all valid names.

What will be the output of the following code? ```python x = 5 y = 2 print(x // y) ```

• `2.5`

• `2`

• `3`

• `2.0`

Answer explanation

The code uses the floor division operator '//' which returns the largest integer less than or equal to the division result. Here, 5 // 2 equals 2, making '2' the correct output.

Which function is used to convert a string to an integer in Python?

• `str()`

• `int()`

• `float()`

• `bool()`

Answer explanation

The `int()` function is used to convert a string to an integer in Python. The other options serve different purposes: `str()` converts to a string, `float()` converts to a float, and `bool()` converts to a boolean.

What is the data type of the following expression in Python: `3.14`?

• `int`

• `str`

• `float`

• `bool`

Answer explanation

The expression `3.14` is a decimal number, which in Python is classified as a `float`. This data type is used for representing real numbers that contain a fractional part.