Getting Started

Python - IntroductionPython - Hello World ProgramPython - SyntaxPython - Data TypesPython - Variables


Python - Arithmetic OperatorsPython - Relational OperatorsPython - Logical OperatorsPython - Assignment OperatorsPython - Bitwise OperatorsPython - Membership OperatorsPython - Identity OperatorsPython - Increment and Decrement Operators


Python - If Else statement


Python - While LoopPython - For Loop


Python - NumbersPython - Number Conversion


Python - StringsPython - String OperatorsPython - String FormattingPython - String MethodsPython - String Format Method


Python - ListPython - List Methods


Python - Tuple


Python - SetPython - Set Methods


Python - DictionaryPython - Dictionary Methods


Python - FunctionsPython - Functions - Variable length argumentsPython - Lambda Function

Scope of Variables

Python - Scope of Variables


Python - ModulesPython - Math ModulePython - JSON ModulePython - datetime ModulePython - time Module


Python - Read input from keyboard


Python - File Handling

Exception Handling

Python - Exception Handling


Python - Classes and ObjectsPython - Class Constructor __init__ methodPython - Class Destructor __del__ methodPython - Built-in Class AttributesPython - InheritancePython - Method OverridingPython - Method Overloading

Package Management

Python - PIP

Python - MySQL

Python - MySQL - Getting StartedPython - MySQL - Insert dataPython - MySQL - Select dataPython - MySQL - Update dataPython - MySQL - Delete data

Python - CSV

Python - Read data from CSV filePython - Write data in CSV file

Python - Variables


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In this tutorial we will learn to work with variables in Python.

Variables are named memory locations which holds some value. And these values can be changed later.

We don't have to explicitly declare variables in Python to reserve memory space. They are automatically declared and memory is allocated when a variable is assigned a value.

Creating Variables

Following are the rules that we must remember while naming a variable in Python.

  • We can only use letters (uppercase A-Z and lowercase a-z), digits (0-9) and underscore (_) to name a variable.
  • Variable name must start with a letter or underscore.
  • We can't start a variable name with digit.
  • Variable name is case-sensitive.

Following are some of the valid variable names.


Following are invalid variable names.

1account      # can't start with digit
user-name     # con't use -

Case sensitive

Variables are case-sensitive in Python which means lowercase variable name and uppercase variable name are treated differently.

Following variables are treated differently even though they are the same word.

score = 10
SCORE = 10

Assign value to a variable

We use the = sign to assign value to a variable.

In the following example we are assigning integer value to a variable x.

x = 10

Same value assignment

We can assign same value in one go to multiple variables in Python.

In the following example we are assigning value 10 to the three variables.

x = y = z = 10

Different value assignment

We can assign different values in one go to different variables in Python.

In the following example we are assigning 1 to a, 3.14 to b, 'Hello World' to msg and 1+2j to c.

a, b, msg, c = 1, 3.14, 'Hello World', 1 + 2j

Swap value of variables

If there are two variables and we want to swap their values without using any third variable then we can write the following code in Python.

var1, var2 = var2, var1

In the following example we have two variables a and b and they hold values 10 and "Happy" respectively and we are swapping their values.

# before
a = 10
b = "Happy"
print("before:", a, b)

# swap
a, b = b, a

# after
print("after:", a, b)

We will get the following output.

before: 10 Happy
after: Happy 10