A class can be thought of as a way of assigning a name to a set of specific functions and variables that are all associated with a common piece of an application.

The code for a class differs in two main ways from regular Python code.

Firstly, you will see the class keyword before the name of the class, followed by a colon and an indented scope. This is the syntax for telling Python that everything within this scope belongs to the class.

Secondly, all functions defined will have self as their first argument (unless they are static or class methods). This is automatically passed in via Python itself and so will cause calls to the function to appear to need one fewer argument than the definition.

The purpose of the self argument is to give each function (which, when in the scope of a class, is known as a method instead) access to the instance's other...

We will begin by defining the classes which will be used in order to separate out different aspects of the game of blackjack. We will model three of the components of the game:

• Card: A basic playing card. The card belongs to a suit and is worth a certain value.
• Deck: A collection of cards. The deck shrinks as cards are drawn and contains 52 unique cards.
• Hand: Each player's assigned cards. A hand is what defines each player's score and thus who wins.

Let's begin with the simplest concept—the Card.

The Card class will be the first class we define, as both of our other classes will need to use it. Open up a new file and type the following code:

import random

class...

We will define the game's main loop within the class __init__ method so that to begin playing, we simply need to create an instance of this class:

class Game:
    def __init__(self):
        playing = True

        while playing:
            self.deck = Deck()
            self.deck.shuffle()

            self.player_hand = Hand()
            self.dealer_hand = Hand(dealer=True)

            for i in range(2):
                self.player_hand.add_card(self.deck.deal())
                self.dealer_hand.add_card(self.deck.deal())

            print("Your hand is:")
            self.player_hand.display()
            print()
            print("Dealer's hand is:")
            self.dealer_hand.display()

We start off our loop with a Boolean which will be used to track whether or not we are still playing the game.

If we are, we need a shuffled...

Since we now have a working game, what is the motivation to continue with this project? Isn't the command-line interface good enough for a lot of games?

Let's briefly compare the suitability of command-line interfaces versus graphical interfaces for Python programs.

When creating a program which runs on the command line, there are essentially only two ways to get input from the user.

The first is by parsing command-line arguments. These are the extra information written on the same line when running an executable from the command line. For example: python3 -i blackjack.py. Here, we  have passed in a flag of -i telling the interpreter to end in interactive mode, and the filename...

In this chapter, we have gone over how to create and use classes in Python. We have seen that they allow for code reuse by defining methods, but these methods can have different outcomes depending on which attributes the particular instance of a class holds.

We have briefly looked at the concept of polymorphism and how easy it is to do using Python's dynamic typing.

Our basic command-line version of the blackjack game has been written and is fully playable. We are now prepared to take this up to the next level in the following chapter by utilizing some new Tkinter widgets.

The choice of interface options has been discussed so that we now know why learning a graphical framework such as Tkinter is a good idea to allow for familiarity and ease of use for our applications. This serves as our motivation for the next step with our game, so that we may make it interesting...