Variables and Assignment in Python
What is a Variable?
A variable is a name that refers to a value stored in memory.
It acts as a reference, not a storage container.
Unlike other languages, Python variables do not store values but rather point to objects in memory.
Example:
x = 10 # x refers to an object holding the value 10
Variables Are Not Storage Containers
In Python, variables are like labels attached to objects in memory.
Assigning a variable does not copy data; it creates a reference.
Example:
a = [1, 2, 3] # a points to a list object
b = a # b refers to the same list, not a copy
Changing b affects a because both reference the same object.
b.append(4) # Modifies the list
print(a) # Output: [1, 2, 3, 4]
Variable Assignment in Python
The assignment operator (=) is used to bind variables to values.
Python allows multiple assignments in a single statement.
Example:
a, b, c = 5, 10, 15
name = “Alice”
Multiple Assignment in Python
Python allows assigning multiple values to multiple variables in one line.
This feature makes code more concise and readable.
x, y, z = 1, 2, 3 # Assigning different values
a = b = c = 100 # Assigning the same value to multiple variables
Swapping values using multiple assignment:
a, b = b, a # Swap values of a and b
Dynamic Typing in Python
Python is dynamically typed.
The type of a variable is determined at runtime.
You can reassign a variable to a different type.
x = 5 # Integer
x = “Hello” # Now a string
Best Practices for Variable Naming
Use meaningful variable names.
Follow the PEP 8 naming conventions.
Avoid using Python keywords as variable names.
Example of valid names:
student_name = “John”
total_marks = 95
Summary
Variables in Python are references, not storage containers.
The assignment operator = creates a reference.
Python supports multiple assignments.
Python supports dynamic typing.
Follow best practices for variable naming.
Thank You!
