02. Variables, Data Types, and Input–Output Free Online FlashCards

What is a variable?

A variable is a named reference to a value, allowing a program to store information and use it later.

What naming convention uses underscores between words?

snake_case separates words with underscores, as in maximum_speed.

What rules apply to Python identifiers?

Python identifiers may contain letters, digits, and underscores, but cannot begin with a digit, use reserved keywords, or ignore case differences.

Which Python operator performs assignment?

The single equals sign (`=`) assigns the evaluated result on the right to the name on the left.

Which operator tests equality in Python?

The double equals operator (`==`) compares values and asks whether they are equal; it does not assign a value.

How does Python conventionally represent constants?

Python does not enforce constants directly. Programmers conventionally use uppercase names, such as DAYS_PER_WEEK, for values that should not change.

Which Python type represents whole numbers?

`int` represents an integer, or whole number, such as -4, 0, or 27.

Which Python type represents True or False?

`bool` represents a Boolean logical value: `True` or `False`.

What does a data type determine?

A data type describes the kind of value stored and the operations that can be performed on it.

Which function converts a value to an integer?

`int()` converts a value to an integer when possible, such as `int("42")`, which produces 42.

What type does Python input() return?

Python’s `input()` function returns the user’s entry as a string, even when the entry consists of digits.

What does Python’s print() function do?

`print()` writes values to standard output, such as the screen. It can display one or several values.