What are *args & **kwargs? And why would we use it?

*args

The *args is a magic variable in Python which allows us to create a function which takes a non-keyworded variable length arguments in the form of a tuple and we simply iterate it to access each arguments.

We may not know the exact numbers of variables passed in a function beforehand so *args helps to resolve this problem.

Actually only * can be used to denote the variables being received in the form of tuples.

*args Example

In the following example, we make a function to multiply for any given numbers passed to the function multiply to illustrate concept of *args

def multiply (*args):
	result = 1
	# iteration & multiplication
	for numbers in args:
			result = result * numbers
	print(result)

# function call	
multiply(4, 5) # outputs 20
multiply(3, 4, 5) # outputs 60
multiply(3, 5, 10, 6) # outputs 900

**kwargs

**kwargs is also a magic variable in Python which allows us to create a function that takes any number of keyword arguments. Arguments can be passed as a key value pairs or in the form of dictionary data type. We use **kwargs when we want to handle named arguments in a function.

**kwargs Example

Following program prints the values of a given keys passed to illustrate the concept of **kwargs

def print_values(**kwargs):
		# iteration
		for key, value in kwargs.items ( ):
				print("Value of {0} is {1}".format(key, value))

# function call 
print_values(my_name = "Alex", your_name = "Alice")

Output

Value of my_name is Alex
Value of your_name is Alice