Keyword arguments to function **kwargs

Introduction:

  • The **kwargs parameter in a function allows the function to accept any number of keyword (named) arguments.
  • The datatype of kwargs is a dictionary, which means keywords and their respective argument values are stored as key:value pairs.

**Example: Python kwargs:

  • Let's demonstrate a simple use case where we create a function that can accept any number of keyword arguments.

Python Program:

python
def myFunction(**kwargs):
    for kw in kwargs:
        print(kw, '-', kwargs[kw])

if __name__ == "__main__":
    myFunction(a = 24, b = 87, c = 3, d = 46)

Output:

a - 24
b - 87
c - 3
d - 46

kwargs is Just a Parameter Name:

  • You can use any name instead of kwargs. The important part is the double asterisks **, which indicates that this parameter will accept any number of named arguments.

  • Example using a different name:

    python
    def myFunction(**computers):
    for kw in computers:
        print(kw, '-', computers[kw])

if __name__ == "__main__":
    myFunction(dell = 1299.50, asus = 1870.00, hp = 1990.50)

Output:

dell - 1299.5
asus - 1870.0
hp - 1990.5

kwargs is a Dictionary:

  • The datatype of kwargs is a dictionary. You can use all the dictionary methods on kwargs.

  • Example using dict.items() method:

    python
    def myFunction(**kwargs):
    for key, value in kwargs.items():
        print(key, '-', value)

if __name__ == "__main__":
    myFunction(a = 24, b = 87, c = 3, d = 46)

Output:

a - 24
b - 87
c - 3
d - 46

**Using kwargs with Other Parameters:

  • You can use **kwargs along with other parameters in your function definition.

    python
    def myFunction(x, y, **kwargs):
    print(x)
    print(y)
    for key, value in kwargs.items():
        print(key, '-', value)

if __name__ == "__main__":
    myFunction("ABC", "MNO", a = 24, b = 87, c = 3, d = 46)

Output:

ABC
MNO
a - 24
b - 87
c - 3
d - 46

**Using *kwargs with args:

  • While **kwargs accepts any number of named arguments, *args accepts any number of positional arguments.

  • Example using both *args and **kwargs:

    python
    def myFunction(*args, **kwargs):
    print(args)
    print(kwargs)

if __name__ == "__main__":
    myFunction("hello", "mars", a = 24, b = 87, c = 3, d = 46)

Output:

('hello', 'mars')
{'a': 24, 'b': 87, 'c': 3, 'd': 46}

Summary:

  • In this tutorial, we learned how to use **kwargs to accept any number of named arguments in a function. Practice using **kwargs and *args to create flexible and versatile functions in your Python programs