Python program मध्ये data वापरताना त्या data ला meaningful नाव देण्याची गरज असते. त्या नावामुळे आपण value पुन्हा वापरू शकतो, बदलू शकतो आणि program अधिक readable बनवू शकतो. या chapter मध्ये variable म्हणजे काय, variable कसा create करायचा, value assign/reassign कशी करायची, multiple assignment, variable naming rules आणि naming conventions शिकणार आहोत.

या examples साठी Python 3.14 stable series लागू आहे. 7 September 2026 रोजी Python 3.14.7 ही latest stable Python 3 release आहे.

Learning Outcomes#

हा chapter पूर्ण केल्यानंतर तुम्ही independently:

variable म्हणजे काय हे explain करू शकाल.
Python मध्ये variable create करून value assign करू शकाल.
existing variable ची value reassign करू शकाल.
एकाच statement मध्ये multiple variables assign करू शकाल.
valid आणि invalid variable names ओळखू शकाल.
Python चे case-sensitive naming behavior समजू शकाल.
naming rules आणि naming conventions मधला फरक सांगू शकाल.
readable snake_case variable names लिहू शकाल.
variable-related common syntax आणि runtime mistakes diagnose करू शकाल.
basic variable interview questions confidently answer करू शकाल.

What is a Variable?#

कल्पना करा की application मध्ये student चे नाव वापरायचे आहे.

आपण प्रत्येक ठिकाणी थेट "Sneha" लिहू शकतो.

PYTHON

print("Sneha")
print("Sneha")
print("Sneha")

पण उद्या student चे नाव बदलले तर प्रत्येक ठिकाणी value manually बदलावी लागेल.

याऐवजी:

PYTHON

student_name = "Sneha"

print(student_name)
print(student_name)
print(student_name)

आता "Sneha" या value ला आपण student_name हे meaningful नाव दिले आहे.

Definition

A variable is a name that refers to a value in a program.

मराठी अर्थ

Variable म्हणजे program मधील एखाद्या value ला दिलेले नाव.

उदाहरण:

PYTHON

course_name = "Python Beginner Course"

इथे:

TEXT

course_name          =          "Python Beginner Course"
    ↓                 ↓                    ↓
variable name     assignment             value
                  operator

महत्त्वाचे: Beginner level वर variable ला "value ठेवण्याचा box" असे समजणे सोपे वाटू शकते, पण Python मध्ये अधिक अचूक समज अशी आहे:

Variable name एका value/object कडे refer करते.

Python documentation assignment ला name आणि value यांच्यात binding/rebinding म्हणून describe करते.

Why Do We Need Variables?#

Suppose तुम्ही course enrollment system तयार करत आहात.

तुमच्याकडे खालील information आहे:

PYTHON

student_name = "Aarav"
course_name = "Python Beginner Course"
progress = 20

आता application मध्ये meaningful names वापरल्यामुळे code लगेच समजतो.

Compare:

PYTHON

x = "Aarav"
y = "Python Beginner Course"
z = 20

आणि:

PYTHON

student_name = "Aarav"
course_name = "Python Beginner Course"
progress = 20

दुसरा code अधिक readable आहे.

Variables मुळे आपण:

values ला meaningful names देऊ शकतो
values पुन्हा वापरू शकतो
values बदलू शकतो
code readable ठेवू शकतो
program state represent करू शकतो

Creating Variables#

Definition

A variable is created when a value is assigned to a name.

मराठी अर्थ

एखाद्या नावाला value assign केली की Python मध्ये त्या नावाचा variable तयार होतो.

Python मध्ये basic variable तयार करण्यासाठी Java सारखी separate declaration आवश्यक नाही.

PYTHON

student_name = "Riya"

इथे student_name या नावाला "Riya" value assign झाली.

आता:

PYTHON

print(student_name)

Expected Output:

TEXT

Riya

आणखी examples#

PYTHON

city = "Pune"
experience = 2
course_completed = False

या chapter मध्ये आपण values चे वेगवेगळे data types खोलात शिकणार नाही. ते Python Data Types chapter मध्ये शिकू.

Variable Creation Flow#

TEXT

student_name = "Riya"
        │
        ▼
Right-side value is evaluated
        │
        ▼
"Riya"
        │
        ▼
The name student_name is bound to that value
        │
        ▼
student_name can now be used

उदाहरण:

PYTHON

student_name = "Riya"
print(student_name)

Assigning Values#

Definition

Assignment connects a variable name with a value.

मराठी अर्थ

Assignment म्हणजे variable च्या नावाला value जोडणे.

Python मध्ये basic assignment साठी = वापरतो.

PYTHON

city = "Mumbai"

इथे:

city → variable name
= → assignment operator
"Mumbai" → assigned value

आणखी example#

PYTHON

employee_name = "Rahul"
employee_id = 105
office = "Pune"

print(employee_name)
print(employee_id)
print(office)

Expected Output:

TEXT

Rahul
105
Pune

Assignment करताना Execution Order#

हे statement बघा:

PYTHON

username = "Neha"

Conceptually Python:

right side ची value evaluate करतो
त्या value ला username नाव bind करतो
त्यानंतर username वापरता येतो

म्हणून:

PYTHON

print(username)

हे assignment नंतर valid आहे.

पण:

PYTHON

print(username)
username = "Neha"

या वेळी पहिल्या line वर username अजून defined नसेल तर NameError होईल.

Reassigning Values#

Real application मध्ये values नेहमी permanent नसतात.

उदाहरण:

Student ची course progress सुरुवातीला:

PYTHON

progress = 10

नंतर:

PYTHON

progress = 40

आता progress ची current value 40 आहे.

Definition

Reassignment means binding an existing variable name to a new value.

मराठी अर्थ

Existing variable ला नवीन value assign करणे म्हणजे reassignment.

उदाहरण:

PYTHON

city = "Pune"

print(city)

city = "Mumbai"

print(city)

Expected Output:

TEXT

Pune
Mumbai

काय झाले?#

TEXT

Initially:

city ─────► "Pune"

After:

city ─────► "Mumbai"

city = "Mumbai" हे statement previous assignment replace करते.

Reassignment in a Real Scenario#

Suppose user ने delivery address change केला.

PYTHON

delivery_city = "Pune"

print(delivery_city)

delivery_city = "Nagpur"

print(delivery_city)

Expected Output:

TEXT

Pune
Nagpur

Application च्या current state नुसार variable ची value बदलू शकते.

Same Variable, Different Values#

Python मध्ये variable लिहिताना त्याचा type declare करावा लागत नाही.

उदाहरण:

PYTHON

value = 100
value = "Completed"

हे Python मध्ये allowed आहे.

पण values चे types, type checking आणि type() पुढच्या Python Data Types chapter मध्ये detail मध्ये शिकू.

Multiple Assignment#

कधी कधी आपल्याला अनेक variables create करायचे असतात.

Python यासाठी convenient assignment syntax देते.

Assign Different Values to Multiple Variables#

Definition

Multiple assignment allows multiple variable names to receive values in one statement.

मराठी अर्थ

एका statement मध्ये अनेक variables ला values assign करता येतात.

उदाहरण:

PYTHON

name, city, country = "Asha", "Pune", "India"

हे conceptually:

PYTHON

name = "Asha"
city = "Pune"
country = "India"

यासारखे आहे.

Use:

PYTHON

name, city, country = "Asha", "Pune", "India"

print(name)
print(city)
print(country)

Expected Output:

TEXT

Asha
Pune
India

Values position नुसार variables ला assign होतात.

TEXT

name       city       country
  ↑          ↑           ↑
"Asha"     "Pune"      "India"

Assign Same Value to Multiple Variables#

जर अनेक variables ना same value द्यायची असेल:

PYTHON

x = y = z = 0

नंतर:

PYTHON

print(x)
print(y)
print(z)

Expected Output:

TEXT

0
0
0

हे syntax initialization सारख्या simple cases मध्ये useful असू शकते.

Swapping Two Variables#

Python मध्ये दोन variables च्या values सहज exchange करता येतात.

PYTHON

first = "Tea"
second = "Coffee"

first, second = second, first

print(first)
print(second)

Expected Output:

TEXT

Coffee
Tea

Before:

TEXT

first  → Tea
second → Coffee

After:

TEXT

first  → Coffee
second → Tea

Temporary variable manually create करण्याची गरज नाही.

Number of Variables and Values Must Match#

हे valid आहे:

PYTHON

x, y = 10, 20

पण:

PYTHON

x, y = 10, 20, 30

या assignment मध्ये left side वर दोन targets आणि right side वर तीन values आहेत.

Beginner level वर लक्षात ठेवा:

Simple multiple assignment मध्ये variables आणि supplied values योग्य प्रकारे match झाले पाहिजेत.

Advanced unpacking पुढील योग्य chapter मध्ये शिकता येईल.

Variable Naming Rules#

Variable name लिहिण्यासाठी Python चे काही language rules आहेत.

Definition

Variable naming rules define which names are syntactically valid Python identifiers.

मराठी अर्थ

Python मध्ये कोणती variable names technically valid आहेत हे naming rules ठरवतात.

Python identifiers मध्ये letters, underscore आणि digits वापरता येतात; digit पहिल्या character म्हणून वापरता येत नाही. Names case-sensitive आहेत आणि reserved keywords ordinary identifiers म्हणून वापरता येत नाहीत.

Rule 1 — Name Cannot Start With a Digit#

Valid:

PYTHON

student1 = "Amit"
course2 = "Python"

Invalid:

PYTHON

1student = "Amit"
2course = "Python"

Better:

PYTHON

student1 = "Amit"
course2 = "Python"

Rule 2 — Letters, Digits and Underscore Can Be Used#

Valid:

PYTHON

student_name = "Sneha"
student2 = "Rahul"
_score = 80

Python technically supports a wider range of Unicode identifiers too, but production code मध्ये simple readable ASCII English names वापरणे beginner साठी अधिक practical आहे.

Rule 3 — Spaces Are Not Allowed Inside a Variable Name#

Invalid:

PYTHON

student name = "Asha"

Correct:

PYTHON

student_name = "Asha"

Underscore शब्द वेगळे करण्यासाठी useful आहे.

Rule 4 — Hyphen Is Not Used as Part of a Variable Name#

Invalid:

PYTHON

student-name = "Asha"

Correct:

PYTHON

student_name = "Asha"

- हा variable-name separator नाही.

Rule 5 — Python Keywords Cannot Be Ordinary Variable Names#

Invalid:

PYTHON

class = "Beginner"

Invalid:

PYTHON

for = 10

class आणि for Python keywords आहेत.

Correct:

PYTHON

course_level = "Beginner"
loop_count = 10

Rule 6 — Variable Names Are Case-Sensitive#

हे तीन different names आहेत:

PYTHON

name = "Asha"
Name = "Rahul"
NAME = "Neha"

Example:

PYTHON

city = "Pune"
City = "Mumbai"

print(city)
print(City)

Expected Output:

TEXT

Pune
Mumbai

city आणि City same variable नाहीत.

Rule 7 — Special Symbols Should Not Be Used in Ordinary Variable Names#

Invalid examples:

PYTHON

$user = "Asha"
user@name = "Asha"
total% = 50

Use:

PYTHON

user = "Asha"
user_name = "Asha"
total_percentage = 50

Naming Rules vs Naming Conventions#

हा distinction खूप important आहे.

Naming Rule#

Rule break केला तर code invalid होऊ शकतो.

PYTHON

2student = "Asha"

हे invalid आहे.

Naming Convention#

Convention break केली तरी code run होऊ शकतो, पण code quality कमी होऊ शकते.

उदाहरण:

PYTHON

studentName = "Asha"

हे Python मध्ये valid असू शकते.

पण सामान्य Python style:

PYTHON

student_name = "Asha"

म्हणून:

Rules decide whether a name is valid. Conventions help make a valid name readable and consistent.

Naming Conventions#

Use snake_case for Normal Variable Names#

Definition

snake_case writes lowercase words separated by underscores.

मराठी अर्थ

अनेक शब्दांच्या variable name मध्ये lowercase words underscore ने वेगळे लिहिण्याची style म्हणजे snake_case.

Examples:

PYTHON

student_name = "Ravi"
course_name = "Python"
total_marks = 450
delivery_city = "Pune"

PEP 8 recommends lowercase variable names with underscores between words when needed for readability.

Use Meaningful Names#

Weak:

PYTHON

x = "Python Beginner Course"

Better:

PYTHON

course_name = "Python Beginner Course"

Weak:

PYTHON

p = 999

Better:

PYTHON

course_price = 999

Reader ला code समजण्यासाठी guess करावे लागू नये.

Avoid Unnecessarily Long Names#

Too vague:

PYTHON

x = "Pune"

Too long:

PYTHON

the_city_where_the_student_currently_lives = "Pune"

Better:

PYTHON

student_city = "Pune"

Goal:

Clear + concise + meaningful

Avoid Confusing Single-Letter Names#

PEP 8 specifically discourages l, O आणि I single-character names कारण काही fonts मध्ये ते 1 किंवा 0 सारखे दिसू शकतात.

Weak:

PYTHON

l = 10
O = 20
I = 30

Better:

PYTHON

length = 10
order_count = 20
item_count = 30

Do Not Shadow Important Built-in Names Without a Good Reason#

Python मध्ये काही useful built-in names आहेत.

उदाहरण:

PYTHON

list = "Students"

हे काही contexts मध्ये syntactically valid असू शकते, पण आता list नावाचा built-in वापरताना confusion निर्माण होऊ शकतो.

Better:

PYTHON

student_list_name = "Students"

Similarly avoid careless names such as:

PYTHON

str = "Hello"
type = "premium"
sum = 100

जर तुम्हाला ते built-ins म्हणून नंतर वापरायचे असतील तर अशा naming मुळे problem निर्माण होऊ शकतो.

Constants: UPPER_CASE Convention#

Python language normal variables सारखीच assignment वापरते, पण project मध्ये "ही value बदलू नये" असा developer intent दाखवण्यासाठी constants साठी uppercase convention वापरली जाते.

PYTHON

MAX_ATTEMPTS = 3
DEFAULT_LANGUAGE = "Marathi"

हा language enforcement rule नाही; ही naming convention आहे.

Practical / Real-World Application#

Scenario: Course Enrollment#

Suppose तुम्ही online learning application बनवत आहात.

New enrollment साठी:

PYTHON

student_name = "Sneha"
course_name = "Python Beginner Course"
course_status = "Not Started"
progress = 0

User course सुरू करतो.

PYTHON

course_status = "In Progress"
progress = 15

Complete example:

PYTHON

student_name = "Sneha"
course_name = "Python Beginner Course"
course_status = "Not Started"
progress = 0

print(student_name)
print(course_name)
print(course_status)
print(progress)

course_status = "In Progress"
progress = 15

print(course_status)
print(progress)

Expected Output:

TEXT

Sneha
Python Beginner Course
Not Started
0
In Progress
15

इथे आपण:

meaningful variables तयार केले
initial values assign केल्या
बदललेली application state reassign केली
consistent naming convention वापरली

Another Practical Example: Delivery Details#

PYTHON

customer_name = "Rohan"
delivery_city = "Pune"
delivery_status = "Pending"

print(customer_name)
print(delivery_city)
print(delivery_status)

delivery_city = "Mumbai"
delivery_status = "Confirmed"

print(delivery_city)
print(delivery_status)

Expected Output:

TEXT

Rohan
Pune
Pending
Mumbai
Confirmed

यामुळे variable फक्त academic concept नसून application state represent करण्यासाठी fundamental आहे हे दिसते.

Common Mistakes & Misconceptions#

Misconception 1 — "Variable म्हणजे permanently fixed value"#

का believable वाटते?

कारण आपण variable create करताना एक value assign करतो.

पण:

PYTHON

status = "Pending"
status = "Completed"

Correct understanding:

Variable name पुन्हा दुसऱ्या value ला bind होऊ शकते.

Misconception 2 — "`=` म्हणजे mathematical equality"#

Programming assignment मध्ये:

PYTHON

score = 100

याचा अर्थ:

score ला 100 assign करा.

हे mathematical equation solve करणे नाही.

Comparison operations आपण appropriate पुढील chapter मध्ये शिकू.

Misconception 3 — "Variable वापरण्याआधी declaration line आवश्यक आहे"#

Python basic assignment मध्ये:

PYTHON

name = "Asha"

हेच name create/bind करण्यासाठी पुरेसे आहे.

Separate:

TEXT

declare name

अशी ordinary beginner syntax नाही.

Misconception 4 — "`userName` invalid आहे कारण Python snake_case वापरतो"#

userName syntax च्या दृष्टीने valid असू शकते.

पण:

PYTHON

user_name

हे Python naming convention ला अधिक consistent आहे.

Rule आणि convention confuse करू नका.

Misconception 5 — `name` आणि `Name` Same आहेत#

Wrong.

PYTHON

name = "Riya"
Name = "Aarav"

हे दोन वेगळे identifiers आहेत.

Misconception 6 — कोणतेही readable word variable म्हणून वापरता येते#

नाही.

PYTHON

class = "Python"

class reserved keyword असल्यामुळे ordinary variable name म्हणून वापरता येत नाही.

Hands-On Practice#

Practice 1 — Create Meaningful Variables#

Requirement#

खालील student information variables मध्ये store करा:

name = Anaya
city = Pune
course = Python

Learner Task#

Meaningful snake_case names वापरा आणि values print करा.

Hint 1#

Assignment syntax:

TEXT

variable_name = value

Hint 2#

तीन separate variables create करा.

Solution#

PYTHON

student_name = "Anaya"
student_city = "Pune"
course_name = "Python"

print(student_name)
print(student_city)
print(course_name)

Expected Output:

TEXT

Anaya
Pune
Python

Practice 2 — Reassign a Status#

Requirement#

Initial order status "Pending" आहे. नंतर ते "Shipped" करा.

Learner Task#

एकच variable वापरा.

Hint#

Existing name ला पुन्हा value assign करा.

Solution#

PYTHON

order_status = "Pending"
print(order_status)

order_status = "Shipped"
print(order_status)

Expected Output:

TEXT

Pending
Shipped

Practice 3 — Multiple Assignment#

Requirement#

एका statement मध्ये:

name = "Ravi"
city = "Nagpur"
country = "India"

assign करा.

Solution#

PYTHON

name, city, country = "Ravi", "Nagpur", "India"

print(name)
print(city)
print(country)

Practice 4 — Find Invalid Names#

खालील names classify करा:

TEXT

student_name
2student
student2
student-name
class
StudentName

Solution#

Name	Syntax Valid?	Comment
`student_name`	Yes	Recommended style
`2student`	No	Starts with digit
`student2`	Yes	Digit after first character is allowed
`student-name`	No as one identifier	Hyphen is not part of a normal identifier
`class`	No	Python keyword
`StudentName`	Yes	Valid, but not preferred style for normal variables

Practice 5 — Improve Naming Quality#

Rewrite:

PYTHON

n = "Aarav"
c = "Python Beginner Course"
p = 999

Solution#

PYTHON

student_name = "Aarav"
course_name = "Python Beginner Course"
course_price = 999

Why better?

Reader ला प्रत्येक value चा purpose लगेच समजतो.

Interview Preparation#

1. What is a variable in Python?

A variable is a name that refers to a value or object in a Python program.

What the interviewer is testing: Whether you understand that a Python variable is a name bound to a value rather than a permanently typed storage box.

2. How do you create a variable in Python?

A variable is created by assigning a value to a name.

PYTHON

student_name = "Asha"

Python does not require a separate declaration for ordinary variables before assignment.

3. What is variable assignment?

Variable assignment binds a name to a value using the assignment operator =.

PYTHON

score = 100

Here, the name score refers to the assigned value.

4. What is reassignment?

Reassignment means assigning a new value to an existing variable name.

PYTHON

status = "Pending"
status = "Completed"

After the second assignment, status refers to "Completed".

5. Can a Python variable be assigned a different kind of value later?

Yes.

PYTHON

value = 10
value = "Done"

Python does not require a fixed type declaration for an ordinary variable name.

A detailed discussion of Python data types belongs to the data-types topic.

6. What are the basic rules for naming variables in Python?

A variable name:

cannot start with a digit
can contain letters, digits and underscores
cannot be a Python reserved keyword
is case-sensitive
cannot contain spaces as part of one identifier

Python also supports valid Unicode identifiers, although simple ASCII names are commonly preferred for broad readability.

7. Are name, Name, and NAME the same variable?

No. Python identifiers are case-sensitive, so these are three different names.

8. What is the difference between a naming rule and a naming convention?

A naming rule determines whether an identifier is syntactically valid.

A naming convention is a style recommendation that improves consistency and readability.

For example:

PYTHON

2student = "Asha"

is invalid because it breaks a language rule.

PYTHON

studentName = "Asha"

can be valid, but:

PYTHON

student_name = "Asha"

better follows standard Python variable naming style.

9. What naming convention is normally used for Python variables?

Python variables normally use lowercase words separated by underscores when necessary.

Example:

PYTHON

student_name = "Asha"

This style is commonly called snake_case.

10. What is multiple assignment in Python?

Multiple assignment allows multiple names to receive values in a single assignment statement.

PYTHON

x, y = 10, 20

Here, x receives 10 and y receives 20.

11. How can you assign the same value to multiple variables?

You can use chained assignment:

PYTHON

x = y = z = 0

All three names are bound to the assigned value.

12. How can two variable values be swapped in Python?

Python supports direct swapping:

PYTHON

first, second = second, first

A separate temporary variable is not required.

13. What happens if you use a variable before assigning it?

If the name cannot be resolved, Python raises a NameError.

Example:

PYTHON

print(score)

If score has not been defined in the applicable scope, the statement fails.

14. Why are meaningful variable names important?

Meaningful names improve readability, maintainability, debugging and communication between developers.

For example:

PYTHON

course_price = 999

communicates more intent than:

PYTHON

p = 999

Quick Revision#

Variable म्हणजे value/object कडे refer करणारे नाव.
Basic assignment:

PYTHON

name = "Asha"

Reassignment:

PYTHON

status = "Pending"
status = "Completed"

Different values:

PYTHON

x, y = 10, 20

Same value:

PYTHON

x = y = z = 0

Swap:

PYTHON

x, y = y, x

Variable name digit ने सुरू करू नका.
spaces आणि normal identifier मध्ये hyphen वापरू नका.
Python keywords variable names म्हणून वापरू नका.
Names case-sensitive आहेत.
Normal variables साठी snake_case prefer करा.
Meaningful, concise names वापरा.
Naming rule आणि naming convention वेगळे आहेत.
Variable वापरण्यापूर्वी त्याला value assign झालेली असणे आवश्यक आहे.

You Should Now Be Able To#

आता तुम्ही:

Python variable explain करू शकता.
basic assignment लिहू शकता.
variable ची value reassign करू शकता.
multiple assignment वापरू शकता.
same value multiple names ला assign करू शकता.
two values swap करू शकता.
valid/invalid identifiers ओळखू शकता.
case sensitivity explain करू शकता.
keywords चुकीने variable names म्हणून वापरणे टाळू शकता.
snake_case variable names लिहू शकता.
unclear variable names improve करू शकता.
basic variable bugs diagnose करू शकता.
beginner-level Variables interview questions answer करू शकता.

Final Challenge#

Scenario#

तुम्ही simple course-registration program चा data तयार करत आहात.

Initial information:

TEXT

Student: Meera
Course: Python Beginner Course
Status: Registered
City: Pune

नंतर:

TEXT

Status becomes Active
City changes to Mumbai

Constraints#

Meaningful snake_case names वापरा.
Initial values assign करा.
Status आणि city reassign करा.
student_name आणि course_name एकाच statement मध्ये assign करण्याचा प्रयत्न करा.
Final values print करा.

Hint 1#

PYTHON

a, b = value1, value2

Hint 2#

Existing variable update करण्यासाठी त्याच नावाला नवीन value assign करा.

Solution#

PYTHON

student_name, course_name = "Meera", "Python Beginner Course"
registration_status = "Registered"
student_city = "Pune"

registration_status = "Active"
student_city = "Mumbai"

print(student_name)
print(course_name)
print(registration_status)
print(student_city)

Expected Output:

TEXT

Meera
Python Beginner Course
Active
Mumbai

Reasoning#

या challenge मध्ये तुम्ही:

variable creation
assignment
multiple assignment
reassignment
meaningful naming
snake_case

हे chapter मधील core concepts एकत्र वापरले.

Practice lab

Learning Outcomes#

What is a Variable?#

Why Do We Need Variables?#

Creating Variables#

आणखी examples#

Variable Creation Flow#

Assigning Values#

आणखी example#

Assignment करताना Execution Order#

Reassigning Values#

काय झाले?#

Reassignment in a Real Scenario#

Same Variable, Different Values#

Multiple Assignment#

Assign Different Values to Multiple Variables#

Assign Same Value to Multiple Variables#

Swapping Two Variables#

Number of Variables and Values Must Match#

Variable Naming Rules#

Rule 1 — Name Cannot Start With a Digit#

Rule 2 — Letters, Digits and Underscore Can Be Used#

Rule 3 — Spaces Are Not Allowed Inside a Variable Name#

Rule 4 — Hyphen Is Not Used as Part of a Variable Name#

Rule 5 — Python Keywords Cannot Be Ordinary Variable Names#

Rule 6 — Variable Names Are Case-Sensitive#

Rule 7 — Special Symbols Should Not Be Used in Ordinary Variable Names#

Naming Rules vs Naming Conventions#

Naming Rule#

Naming Convention#

Naming Conventions#

Use snake_case for Normal Variable Names#

Use Meaningful Names#

Avoid Unnecessarily Long Names#

Avoid Confusing Single-Letter Names#

Do Not Shadow Important Built-in Names Without a Good Reason#

Constants: UPPER_CASE Convention#

Practical / Real-World Application#

Scenario: Course Enrollment#

Another Practical Example: Delivery Details#

Common Mistakes & Misconceptions#

Misconception 1 — "Variable म्हणजे permanently fixed value"#

Misconception 2 — "= म्हणजे mathematical equality"#

Misconception 3 — "Variable वापरण्याआधी declaration line आवश्यक आहे"#

Misconception 4 — "userName invalid आहे कारण Python snake_case वापरतो"#

Misconception 5 — name आणि Name Same आहेत#

Misconception 6 — कोणतेही readable word variable म्हणून वापरता येते#

Hands-On Practice#

Practice 1 — Create Meaningful Variables#

Requirement#

Learner Task#

Hint 1#

Hint 2#

Solution#

Practice 2 — Reassign a Status#

Requirement#

Learner Task#

Hint#

Solution#

Practice 3 — Multiple Assignment#

Requirement#

Solution#

Practice 4 — Find Invalid Names#

Solution#

Practice 5 — Improve Naming Quality#

Solution#

Interview Preparation#

Quick Revision#

You Should Now Be Able To#

Final Challenge#

Scenario#

Constraints#

Hint 1#

Hint 2#

Solution#

Reasoning#

Misconception 2 — "`=` म्हणजे mathematical equality"#

Misconception 4 — "`userName` invalid आहे कारण Python snake_case वापरतो"#

Misconception 5 — `name` आणि `Name` Same आहेत#