Variables

Variables

A variable is used to store data that will be used by the program. This data can be a number, a string, a Boolean, a list or some other data type. Every variable has a name which can consist of letters, numbers, and the underscore character _.

The equal sign = is used to assign a value to a variable. After the initial assignment is made, the value of a variable can be updated to new values as needed.

Variable Names

A variable can have a short name (like x and y) or a more descriptive name (age, grade, grocery_list).

Rules for Python variables:

  • A variable name must start with a letter or the underscore character. It cannot start with a number.
  • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _).
  • Variable names are case-sensitive (num, Num, and NUM are three different variables).

Examples

These are all valid variable names and assignment:

user_name = "@sonny420"
user_id = 100
verified = False

A variable’s value can be changed after assignment

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