Variable Declaration

Unlike some other programming languages, Python doesn't require explicit declaration of variables. You simply assign a value to a name and Python will create the variable for you.

x = 5

Variable Naming Rules

Unlike some other programming languages, Python doesn't require explicit declaration of variables. You simply assign a value to a name and Python will create the variable for you.

• Variable names can contain letters, digits, and underscores.
• A variable name must start with a letter or the underscore character
• They cannot start with a digit.
• Variable names are case-sensitive (age, Age and AGE are three different variables).
• Avoid using reserved words (keywords) such as if, for, while, etc., as variable names.

Variable Types

Python is dynamically typed, meaning you don't have to explicitly declare the type of a variable. The type of the variable is inferred at runtime based on the value assigned to it.

x = 5          # integer
y = 3.14       # float
name = "John"  # string
is_valid = True  # boolean

Variable Reassignment

You can change the value of a variable at any point in your code.

x = 5
x = x + 1

Multiple Assignment

Python allows you to assign multiple variables in a single line.

a, b, c = 5, 10, 15

Constants

While Python doesn't have constants in the same way some other languages do, it's a convention to use uppercase variable names for values that are not supposed to change.

PI = 3.14159