Python learning series | Day-4

What is function ?

A function is an reusable block of code or instruction to perform a specific task with their name.
Function is also called as procedure/sub procedure/method in other programming languages.

why do learn function in python ?

• Code reusability.
• Easy Maintenance --> modification done easly.
• Code Readability.
• Modularity --> better Organized code.
• Easy testing and debugging.

Function structure

• To define function , def keyword to be used.
• The function name should be in verb.
• Function call must be done after the function declaration

1) Basic Structure:

def greet():
    print("Welcome")

greet()

2) Passing Inputs

Arguments and Parameters

• While calling the function we can send an input is named as Arguments.
• While receiving input(value) were the function is declared is named parameters.

def add(no1 , no2): #no1 ,no2 receving the value called parameters
    print(no1 + n02)

add(10, 20)   # 10 , 20 were Arguments

3) Return function

• To send result to back were the function called , we can use return keyword.
• If a function does not have a return statement, it returns None by default.

def add_numbers(x, y):
    return x + y

result = add_numbers(5, 3)
print(result)

Function overloading

• Same function name with different number of arguments or different types of arguments is called function overloading.

def add(no1, no2): 
    print(no1 + no2)

def add(no1, no2, no3):
    print(no1 + no2 + no3)

add(100,200) 

add(5,10,15)