FUNCTIONS - LOCAL & GLOBAL VARIABLES

 Local Variables

In Python, a local variable is a variable that is defined inside a function and can only be used within that function. It exists only while the function is running, and it disappears after the function finishes execution.

def greet():

    message = "Hello, World!"  # 'message' is a local variable

    print(message)

greet()

# print(message)  # This would cause an error because 'message' is not accessible here

NOTES:

• message is a local variable because it's defined inside the greet() function.
• You cannot access message outside the function.
• Local variables are created when the function is called and are destroyed when the function ends.

Why use local variables?

• To keep data private to the function.
• To avoid conflicts with variables in other parts of the program.

 

Global Variables

A global variable is a variable that is defined outside of any function and can be accessed from anywhere in the program.

message = "Hello, World!"  # This is a global variable

def greet():

    print(message)  # Accessing the global variable inside the function

greet()

print(message)  # Also accessible outside the function

 

output:

Hello, World!

Hello, World!

 

Modifying Global Variables Inside a Function:

If you want to change the value of a global variable inside a function, you must use the global keyword:

count = 0  # Global variable

def increment():

    global count

    count += 1  # Modifying the global variable

increment()

print(count)  # Output: 1

 

 Q. Difference between :

Local Variable	Global Variable
Defined inside a function	Defined outside any function
Accessible only in function	Accessible throughout the program
Created when function runs	Created when program starts
Destroyed after function ends	Exists until program ends