Define Types of Variable in Python.

Q.3 Define Types of Variable in Python.

Answer :- 

Types of Variables in Python

• In Python, variables are used to store data, and the type of variable depends on the type of data it holds.

• Python is a dynamically typed language, meaning you do not need to declare the type of a variable explicitly; it is determined automatically at runtime.

Here are the main types of variables in Python. 

1. Global Variables :- 

• Definition: – These are variables declared outside of any function or class. They are accessible throughout the program, including within functions, unless explicitly shadowed by a local variable.

• Scope: Available globally, across all functions and classes.

• Example :- 

x = 10 # Global variable

def display():
print(“Value of x:”, x)

display() # Output: Value of x: 10. 

2. Local Variables

• Definition: Variables declared inside a function or block of code. They are accessible only within that function or block and cease to exist outside of it.

• Scope: Limited to the function or block in which they are defined.

• Example:

def example():
y = 5 # Local variable
print(“Value of y:”, y)

example() # Output: Value of y: 5
# print(y) # This will cause an error as y is not accessible outside the function

3. Instance Variables:-

• Definition: These are variables specific to an object, defined within a class using self. Each object can have its own copy of instance variables.

• Scope: Specific to the object of a class.

• Example:

class Example:
def __init__(self, value):
self.data = value # Instance variable

obj1 = Example(10)
obj2 = Example(20)

print(obj1.data) # Output: 10
print(obj2.data) # Output: 20

4. Class Variables :-

• Definition: Variables shared across all instances of a class. They are defined within the class but outside any instance methods.

• Scope: Shared by all objects of the class.

• Example:

shared_data = “shared” # Class variable

obj1 = Example()
obj2 = Example()

print(obj1.shared_data) # Output: shared
print(obj2.shared_data) # Output: shared

Example.shared_data = “updated” # Modifies the class variable
print(obj1.shared_data) # Output: updated
print(obj2.shared_data) # Output: updated

5.Constants

• Definition: Although Python does not support true constants, variables defined in uppercase by convention are treated as constants and not modified during the program’s execution.

• Scope: Global or local depending on where they are defined.

• Example:

PI = 3.14159 # Constant
GRAVITY = 9.8 # Constant

print(“PI:”, PI)
print(“Gravity:”, GRAVITY)

6. Nonlocal Variables

• Definition: These are variables declared inside a nested function and are not global or local to the current function. They allow access to variables in the nearest enclosing scope that is not global.

• Scope: Limited to the enclosing scope.

• Example :

def outer_function():
x = “outer”

def inner_function():
nonlocal x
x = “inner”
print(“Inner x:”, x)

inner_function()
print(“Outer x:”, x)

outer_function()
# Output:
# Inner x: inner
# Outer x: inner