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Project Breakdown
5:23With all of our object-oriented programming knowledge, it's time to tackle a bigger, more comprehensive project.
[SOUND] You've learned a ton about
object oriented programming in Python.
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You've learned to make your own classes.
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Either from the ground up.
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Or by building on top of
Python's built in classes.
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You've also taken
advantage of magic methods.
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Class methods.
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And properties.
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To make your classes smarter and cleaner.
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You're doing amazing.
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We haven't built anything larger and
more complex together, though.
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You know me.
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I like to build games with
you as a learning tool.
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When I was first planning this course out.
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I wanted to build a terminal
version of Yahtzee.
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With die rolling, and
re-rolling, hand scoring.
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And even human and bot players.
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Yeah, that wasn't as simple
as I thought it would be.
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When I did complete it.
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It was just way too much
to teach in a course.
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So let's scale it back.
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And build something that's less for
one specific game.
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And maybe a bit more universally useful.
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Over the next few videos.
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We'll build a small utility.
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To roll a specific number of dice
with a specific number of sides.
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You could roll two 20-sided dice or
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five six-sided dice or
whatever your game requires.
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While this isn't quite as
exciting as a full game.
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It'll give us a lot more practice
with building smart classes.
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And it'll be a utility we can use for
building other games.
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As we continue working with Python.
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Get a drink or a snack.
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Take a nap if you need it.
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And then let's start.
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By defining exactly what
our code dice should do.
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All right, we want a die that
has a certain number of sides.
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And then a random value between 1 and
the number of sides.
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And we could base this on int.
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But that actually raises
a fair number of issues.
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It's easier and arguably cleaner
to just make our own class.
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We can control the creation of the class.
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And we can make it a little easier
to subclass for other die types.
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Now I've created a directory named yatzy.
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And I've created a file named dice.py.
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You wanna go ahead and do those.
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If they're not in your workspace.
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So then let's import random.
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And lets create our die class.
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So find our init [INAUDIBLE] self.
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I think we want two arguments.
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I think we want a sides.
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And we'll default that to two.
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And let's let them set a value.
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Just in case they want the die
to be four or whatever.
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For testing purposes.
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So, okay, so we take a number of sides and
we take a value.
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And we want to make sure that sides >= 2.
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Otherwise we should raise ValueError(.
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That says, must have at least 2 sides.
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If you can show me a one sided die,
I would love to see it.
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And let's make sure that sides is an int.
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So if not is instance(sides,
int): We're going to raise
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another value error that says
sides must be a whole number.
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Now, arguably, that might ought to be
a type error instead of a value error,.
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But I figured they gave me the wrong
value, so it's a value error.
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So then let's say that self.value = value.
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That was passed in, or
random.randint (1, sides.
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So something between 1 and sides.
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We can't have a number below 1.
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And it can't be above the number
of sides that there are.
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Now, we're not taking into account
if you had a strange die that had
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only even numbers or something like that.
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And we might want to have a check.
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To make sure that value is also an int.
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But I'll leave that up to you.
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Okay, we have enough here to
try out our really simple die.
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So let's come down here.
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And Python from dice import.
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I need to exit.
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Let me get into Yatzy.
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Python from dice import die.
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And then let's say that d is equal to die,
d.value.
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There's 2.
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And let's say d6 is equal to die.
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And sides is equals to 6 and the 6 sides.
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And then we do d6.value
we get 2 there as well.
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All right, so
it rolled a random number for us twice.
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So cool.
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Now, let's go back and let's make
a die class that extends our die.
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But is always a six sided die.
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Right?
Because that's
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a pretty common need, right?
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There are lots of games out
there that need six sided dice.
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The convention is to call a die D.
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And then the number of sides that it has.
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At least in role playing circles.
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So we're gonna call this a d6.
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Ad this is going to extend die.
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But we're gonna override init.
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We're still gonna take value.
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We're not gonna take sides.
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Because we don't care how
many sides they want, right?
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The sides on this is always gonna be six.
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So we're gonna call super and
then the init method.
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We're gonna say size equals six,
and value equals value.
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We'll just pass value on through.
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And that's it for our class.
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Since we set up our Die class
to take a number of sides.
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We can just hardcode that in our D6 class.
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So, let's test this one out.
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So we're gonna import dice and
then we'll say, d6 = dice.D6().
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And then if we do d6.value we get a 3.
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Nice.
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Now we could go further.
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And turn this into a 12 sided or
a 20 sided.
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Or whatever number of sides
the dice in our game require.
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So feel free to do that if you want to.
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