Python Variables

1. Variable Assignment:

You assign a value to a variable using the equal (=) operator. The variable name comes on the left, and the value comes on the right.

# Variable assignment
x = 5
name = "John"

2. Variable Names:

Variable names can consist of letters (both uppercase and lowercase), numbers, and underscores. They cannot start with a number. Python follows a case-sensitive naming convention, so myVar and myvar are considered different variables.

my_var = 10
count = 3

3. Data Types:

Python is dynamically typed, which means you don't need to declare the data type of a variable explicitly. The interpreter infers the data type based on the assigned value.

age = 25       # Integer
height = 5.9   # Float
message = "Hello, World!"  # String

4. Reassignment:

You can change the value of a variable by assigning a new value to it.

x = 5
x = x + 1  # Incrementing x

5. Multiple Assignments:

You can assign values to multiple variables in a single line.

a, b, c = 1, 2, 3

6. Constants:

Although Python doesn't have a built-in constant type, it is a convention to use uppercase names for constants to indicate that the value should not be changed.

PI = 3.14

7. Type Function:

You can use the type() function to determine the type of a variable.

x = 10
print(type(x))  # Output: <class 'int'>

8. None Type:

Python has a special None type that represents the absence of a value or a null value.

result = None

Variables are a fundamental concept in programming, allowing you to store and manipulate data as your program runs. Understanding how to use variables effectively is crucial for writing expressive and functional Python code.