Introduction:

Variables are an important concept in any programming language, including Python. In simple language, a variable is a named location in memory that stores a value. In Python, you can use variables to store any type of data, including numbers, strings, and even complex data structures like lists and dictionaries.

Creating Variables in Python:

To create a variable in Python, you need to give it a name and assign a value to it. Here’s an example:

Name = “Omkar”
Age = 25
Profession = “Software Engineer “

Python Variable Naming Rules:

When creating variables in Python, there are a few rules that you need to follow:
1). Variable names must start with a letter or underscore (_), followed by any combination of letters, digits, and underscores.
2). Variable names are case-sensitive, which means name and Name are two different variables.
3). A variable name cannot start with a number.
4). A variable name can only contain alphanumeric characters and underscores (A-z, 0-9, and _ ).

Python Variable Types:

1). Numbers: Consists of integers, floating-point numbers, and complex numbers.
2). Strings: Consist of characters in quotes.
3). Booleans: Consist of True or False values.
4). Lists: Consist of ordered sequences of elements.
5). Tuples: Consist of ordered, immutable sequences of elements.
6). Sets: Consist of unordered collections of unique elements.
7). Dictionaries – Consist of unordered collections of key-value pairs.

Checking Types of the Variable:

First, we will create some variables.

Name = “ Omkar “
Age = 25
Height = 5.8 ft

To check the type of the variable use the type() function.

print(type(Name))    # Output: <class ‘str’>
print(type(Age))          # Output: <class ‘int’>
print(type(Height))      # Output: <class ‘float’>

To check the address of the variable, use the id() function.

print(id(Name))      # Output: 2623848788368
print(id(Age))       #  Output: 140718085367336
print(id(Height))    # Output: 2623846066576

Value Assignment:

To assign the value to a variable, use the equal sign (=).
Example:
A = 10
Assign the same value to multiple variables.
A = B = C = 10

Multiple Value Assignment:

We can assign different values to different variables at the same time. We separate the variables and their values by commas ‘,’.

Example:
a, b, c = 40, 50, 60
Here,
Value of variable a is 40 , b is 50 and c is 60.

Scope of Variable:

In Python, the scope of a variable determines where in the code the variable can be accessed and used. The scope of a variable is defined by where the variable is created and assigned a value.
There are two types of variable scopes in Python: global scope and local scope.

1). Global Scope:
Variables created outside of any function or class have a global scope. This means that they can be accessed and modified from anywhere in the code, including within functions and classes.
Example:

number = 100         # global variable

def print_number():
    print(number)    # accessing global variable

def modify_number():
    global number    # declaring number as global variable
    number = 200     # modifying global variable

print_number()       # Output: 100
modify_number()
print_number()       # Output: 200

In the example above, the variable number is declared outside of any function, so it has a global scope. The function print_number() can access and print the value of number, and the function modify_number() can modify the value of number by declaring it as a global variable using the global keyword.

2). Local Scope:
Variables created inside a function or class have a local scope. This means that they can only be accessed and modified within that function or class.
Example:

def my_function():
    number = 100  # local variable
    print(number)  # accessing local variable

my_function()  # Output: 100
print(number)  # NameError: name 'number' is not defined

Basic Mathematical Operations Using Variables:

Creating variables and assigning values to them:
a, b = 10 , 20

Performing operations and printing output:

print(a+b) # Addition       Output: 30
print(a-b) # Subtraction    Output: -10
print(a*b) # Multiplication Output: 200
print(a/b) # Division       Output: 0.5

Python Variables