[Python] How to deal with multiple parameters (2)

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This post is continued from
How to deal with multiple parameters (1)

Quick Recap

Last time we learned how to get multiple (unknown number of) arguments when building a function.
By using “*args” as a parameter, we could store multiple arguments in the variable name “args” as a tuple form.
This time we will learn how can multiple (unknown number of) dictionary arguments be passed to one function.

**kwargs

First, let’s check how it works by simply printing out passed arguments.

def showDict(**kwargs):
    print(kwargs)

showDict(a=80, b=70, c=20, d=100)  # {'a': 80, 'b': 70, 'c': 20, 'd': 100}

As you could check above, the parameter with two asterisk **kwargs accepts multiple arguments that has a form of ‘keyword=value’ and stores those in a dictionary variable.

Now, if you utilise .keys() function, this can bring about really synergistic effect like below.

def good_func(**kwargs):
    for key in kwargs.keys():
        print(key, ":", kwargs[key])

good_func(algorithm = 89, discreteMath = 98, statistics = 70, programming = 95)
# output:
# algorithm : 89
# discreteMath : 98
# statistics : 70
# programming : 95

*args + **kwargs

To be more synergistic, you can even use both *args and **kwargs as below.

def amazing_func2(*args, **kwargs):
    for key in kwargs.keys():
        print(key, ":", kwargs[key]*args[0])

amazing_func2(0.5, algorithm = 89, discreteMath = 98, statistics = 70, programming = 95)
# output:
# algorithm : 44.5
# discreteMath : 49.0
# statistics : 35.0
# programming : 47.5

Note that you have to specify which index you will use in args tuple by doing args[0]

These techniques will not only help you write a better programme but also help you have a better understanding on plenty of documentations.