*args and **kwargs in Python

To understand python *args and **kwargs first, we need to know some common problems we face while programming in python and how *args and **kwargs solve them?

Examine the following python code:

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def add(a, b):
    return a+b
 
print(add(5,6))
 
def add(a, b, c, d, e, f):
    return a+b+c+d+e+f
 
print(add(5,6,1,5,2,2))

Show Output

Notice that we have to write a separate function for adding the different number of arguments. We can simplify this by using a list and sum method.

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def add(lst):
    return sum(lst)
 
print(add([5,6,1,5,2,2]))

Show Output

The little burden of using a list, but still we can do it in a more simple way using *args.

What is *args in Python?

*args is a Non-Keyword Argument which can accept the variable number of arguments and stores them as a tuple.

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def what_is_args(*args):
    print(args)
    
what_is_args()

Show Output

Thus helps in making a function more flexible in terms of accepting arguments.

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def add(*args):
    return sum(args)
 
print(add(5,6,4))
print(add(1,1,1,1,1))

Show Output

What to do? to pass variable and different types of arguments to a function.

In this **kwargs comes handy. Let’s see what is it?

What is **Kwargs in Python?

**kwargs is a Keyword argument which can accept different types of arguments and stores them as a dictionary.

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def what_is_kwargs(**kwargs):
    print(kwargs)
    
what_is_kwargs()

Show Output

Without **kwargs:

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def student(name, roll):
    print(name)
    print(roll)
    
student(name="pencil", roll=77)

Show Output

With **kwargs:

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def student(**kwargs):
    print(kwargs)
    print(kwargs['name'])
    print(kwargs['roll'])
 
student(name="pencil", roll=77)

Show Output

It allows a function to accept more than one type of arguments thus makes them more flexible in terms of types of arguments.

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def website(**kwargs):
    print(kwargs['name'])
    print(kwargs['domain'])
    
website(name='Pencil Programmer', domain='https://pencilprogrammer.com')

Show Output

Note: we can use any names instead of args and kwargs, what makes them meaningful is * (single asterisk) to make it Non-Keyword Argument and ** (Double asterisks) to make it Keyword Argument.

Hope now you got little idea about *args and **kwargs in python and will be able to use it in your programs. Any doubts then comment below.

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