Variables and Constants in Python

Variables in Python

Variables store data values in memory. In Python, variable names can consist of letters, numbers, and underscores but cannot start with a number.

Declaring Variables

x = 5        # Integer
name = "Janak"  # String
pi = 3.14    # Float
is_active = True  # Boolean

Multiple Assignments

a, b, c = 10, 20, "Python"
print(a, b, c)  # 10 20 Python

Variable Reassignment

Python allows reassigning variables with different data types.

x = 10
x = "Hello"  # Now x holds a string
print(x)  # Hello

Constants in Python

Python does not have built-in constant support, but constants are usually declared in uppercase by convention.

Declaring Constants

PI = 3.14159
GRAVITY = 9.8

Using Constants

Constants help improve code readability and maintainability.

radius = 5
area = PI * (radius ** 2)
print("Area of the circle:", area)

Conclusion

Variables store data that can change during program execution, while constants hold fixed values by convention. Understanding their usage improves code efficiency and readability.