Topic3:- Python Variables

 

Python Variables

A variable in Python is a named location used to store data in memory.
You can think of a variable as a container that holds a value — such as a number, text, or list - which can change during the execution of a program.

                                                    

 Definition

A variable in Python:

• Is created when you assign a value to it (no need to declare explicitly).
• Acts as a reference to the object (value) stored in memory.

 Syntax

variable_name = value

• variable_name → name of the variable
• = → assignment operator
• value → the data you want to store

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Examples

1. Assigning integer values

x = 10

y = 25

print(x)

print(y)

Output:

10

25

2. Assigning string values

name = "Kavi"

print("Hello,", name)

Output:

Hello, Kavi

 

3. Assigning float values

pi = 3.14159

print("Value of pi:", pi)

Output:

Value of pi: 3.14159

 

4. Assigning multiple variables

a, b, c = 5, 10, 15

print(a, b, c)

Output:

5 10 15

 

5. Assigning same value to multiple variables

x = y = z = 100

print(x, y, z)

Output:

100 100 100

 

Variable Naming Rules

1. Variable names can contain letters, numbers, and underscores (_).
2. They cannot start with a number.
3. Variable names are case-sensitive (Age, age, and AGE are different).
4. Avoid using Python keywords (like if, while, for, etc.) as variable names.

Examples of valid variable names:

name, student_age, total_marks, _count

Examples of invalid variable names:

2name, total-marks, class

 Example Program

# Program to demonstrate variables

name = "Alice"

age = 21

height = 5.4

 print("Name:", name)

print("Age:", age)

print("Height:", height)

Output:

Name: Alice

Age: 21

Height: 5.4