Functions continued:

• Annotating Functions with Types

def is_prime(number: int) -> bool:
    pass

• Documenting the functions with docstrings

def is_prime(number: int) -> bool:
    '''This function will find if the number is prime or not

    Args:
       number (int): The number to be checked 

    Returns:
        True if prime False otherwise
    '''
    pass

• Default arguments

  • Python allows us to write default arguments for functions

• *args and **kwargs in python:

  • In addition to normal arguments in python we can pass two special symbols for arguments
    • Non Keyword arguments (*args)
    • Keyword arguments (**kwargs)
  • Non Keyword arguments

    def sum(*args):
        print(type(args))
        result = 0
        for arg in args:
            result += arg
        return result
  
  
    result = sum(1,2)
    print(result)
    result = sum(1,2,3,4,5,6,7,8,9)
    print(result)
    result = sum()
    print(result)
  

  • Keyword arguments

    def explain_kwargs(**kwargs):
        print(type(kwargs))
        for key, value in kwargs.items():
            print(f"{key} = {value}")
    
    
    explain_kwargs(name='IHub', course='Python', duration='3')
    

    • Combination of keyword and non keyword arguments

    def fun_function(*args, **kwargs):
        print(f"args are {args}")
        print(f"keyword args are {kwargs}")
    
    
    fun_function('python.direct', 'learningthoughts.academy', blog='python.direct')
    

• When we have arguments of different types in one python function the they have to follow the following order

  • arguments
  • default arguments
  • Non key word arguments
  • Keyword arguments

def rule_function(number, debug=True, *args, **kwargs):
    pass

Exceptions

• If an error occurs in your program an exception is raised and traceback message will be shown

def is_even(number):
    return number % 2 == 0

is_even('Hello')

• Now lets Try to learn an approach to handle errors

def is_even(number):
    return number % 2 == 0


try:
    is_even('Hello')
except Exception as e:
    print("Enter the arguments correctly")
finally:
    print('Executed the program successfully')