[Introduction to Udemy Python3 + Application] 53. Dictionary of keyword arguments

** * This article is from Udemy "[Introduction to Python3 taught by active Silicon Valley engineers + application + American Silicon Valley style code style](https://www.udemy.com/course/python-beginner/" Introduction to Python3 taught by active Silicon Valley engineers + application + American Silicon Valley style code style ")" It is a class notebook for myself after taking the course of. It is open to the public with permission from the instructor Jun Sakai. ** **

■ Dictionary of keyword arguments

◆ Example

keyword_augment_dict

def menu(food='beef', drink='wine'):
    print(food, drink)

menu(food='beef', drink='coffee')

result

beef coffee

First, prepare such a sample. Think about when you want to add more than just food and drink.

◆ Dictionary keyword arguments

keyword_augment_dict

def menu(**kwargs):
    print(kwargs)

menu(food='beef', drink='coffee')

result

{'food': 'beef', 'drink': 'coffee'}

By prefixing the argument passed to menu with** My arguments are made into a dictionary.

keyword_augment_dict

def menu(**kwargs):
    for k , v in kwargs.items():
        print(k, v)

menu(food='beef', drink='coffee')

result

food beef
drink coffee

I set up to pull the key and value of the created dictionary and print it.

keyword_augment_dict

def menu(**kwargs):
    for k , v in kwargs.items():
        print(k, v)

d = {
    'food': 'beef',
    'drink': 'ice coffee',
    'dessert': 'ice cream'
}
menu(**d)

result

food beef
drink ice coffee
dessert ice cream

The dictionary created with d is expanded and passed to each set of key and value bymenu (** d).

■ Simultaneous use of ordinary arguments, tuples of positional arguments, and dictionaryization of keyword arguments

◆ Simultaneous use is possible

args

def menu(fruit, *args, **kwargs):
    print(fruit)
    print(args)
    print(kwargs)

menu('banana', 'apple', 'orange', food='beef', drink='wine')

result

banana
('apple', 'orange')
{'food': 'beef', 'drink': 'wine'}

The first banana is passed to fruit as a normal argument, ʻApple and ʻorange are tupled by being passed to * args, beef and wine were dictionaryized by ** kwargs.

◆ Notes

args

def menu(fruit, **kwargs, *args):
    print(fruit)
    print(kwargs)
    print(args)

menu('banana', food='beef', drink='wine', 'apple', 'orange')

result

    def menu(fruit, **kwargs, *args):
                              ^
SyntaxError: invalid syntax

An error will occur if ** kwargs comes first and * args comes after. If you want to use them at the same time, use them in the order of * → **.