In this video, I'm gonna show you howto program Connect four in Python.

By the end of these videos, you have built something that looks like this.

It's a simple two player connect four game with graphics.

I think this is a really good exercise for your beginner to intermediate level python programmers who want to build their skills.

I'll just finish up a game real quick just so you can see how this fully works.

As you see I the diagonal and it's those player one wins school.

We're gonna do something a little bit simpler and then build up to that graphic based Connect four game.

It's a command line.

Connect four game, where you actually mainly type in numbers to drop your pieces so you see the one there to cetera.

All right, so let's start building that just quickly.

I want to mention that I'll be programming and Python three and then using sublime text to is my editor.

I pushed a link to a video on how to set up these things in the description.

So one of the first questions I asked myself when I was writing this game is what is the best way to represent the board.

So by dragging a connect for Bordeaux quick, you can see that it is six rose by seven columns.

And to me, this looks like the perfect structure to represent as a matrix and python.

So that's what we'll d'oh!

So to find a function called create board and that's not gonna accept any inputs, then we're gonna make a a matrix of all zeros with the Dimension six by seven.

And to help us do this, we're gonna import a package called Numb Pie.

And if you haven't already installed this, you can open up a terminal window and just type in pip install numb pie and, as you can see already have it.

So we're gonna use this as followers and say, board equals numb pi dot zeros.

And that's gonna make a matrix of all zeros, which is good for our initial state.

And then the dimensions six rose by seven columns.

Cool.

And then we just need to return that board and we can test to make sure that worked by doing the following create board and then Prince board.

And as you can see if I don't know what happened.

As you can see, if I run that, um, we we do in fact, have this six by seven matrix of all zeros.

So that looks good.

We can begin writing the mean game loop now.

So gonna raid a loop that says while not game over.

And so our life is gonna be running as long as this game over variable is false.

And the only way it becomes true is if someone has a foreign row.

So we need to initialize the game over to be false.

To begin with, goes falls.

And the only way that's going to switch to true is if someone got a four in a row.

So now we're gonna need to We're also gonna want a real quick make our board initialized before we start the game.

Just so we have something to put pieces into.

So we have our board, we have a game over variable.

And now we're gonna want to be ableto ask player one input, and then we're gonna want to eventually be able to ask Ah, ask for player to input.

So this kind of leads us to the problem of Oh, how do we differentiate between whether it's player one or player two's turn, Israel's gonna define another variable appear called turn That's just going to initialize to zero.

So what we're going to say is, if turn equals, equals zero, then we're gonna wanna ask for player Want input?

All right, so in Python, there's a function of built in function called input.

As you can see, it highlights Pollux for May.

So we're gonna say selection equals input.

And then we're, say, player one, make your selection.

So this is what the player one's going to see, and then the way we're gonna initialize this game is we're going to just say they can type in between zero and six.

So this is what the player one should see.

So if I build this you see, we run to this error.

So this is because, um, sublime text doesn't accept this input function.

So my work around for this was I installed a package and sublime called Supply Mari pl I'll put a link in the description of how to install this, and I can run the input function through that.

So now you can see player one make your selection three, and it doesn't do anything with that input right now, but you can see that it's asking me that and I can type in enter.

All right, cool.

So we also just want to make sure that it saves our selection properly.

So when a print selection, I also just want to see, you know, if I'd have been a number, does it actually give me the number?

Or does it give me a string that represents the numbers?

I mean, I also print in type of selection.

I just want to see what we're getting.

So I'm gonna run that again, as you can see ever again, but we're gonna go to supply Mari pl and the link is in the description, as I just said, Run current file.

So two.

And as you can see, it gets too.

But it says it's a string.

So we're gonna want to make sure that it's actually a integer so we can just surround this with aunt input on this should work.

So let's see.

Run that again.

And you can also run this through the command line.

So if you run this in your terminal, go to the directory that the file is in and type in python and then file name.

It will also run.

Justus.

I'm running it in this sublime Ari.

Pl ah, player one make your selection.

Three cool and nice is it says three, and it says the class of that is an int.

So that looks good too.

May.

So now you can save some sort of selection from the user.

And you can also edit this so that it, um, requires you to make a specific number, type in a specific number, but we'll just leave it as like, well, imagine our players air following the directions right now.

All right, cool.

We have that.

And then we're always gonna want to be able to ask for a player to his input.

So that's gonna happen else.

Otherwise, if the turn is not equal to zero, um, then we want to ask for player.

Two inputs of selection equals it will just copied this from above.

And we'll just have the changes to say, player to make your selection.

All right, Cool.

And now, at the end of the turn, no matter whose turn it is, we're gonna want to increase.

Um are turned by one.

So turn plus plus equals one.

So make it in committed by one and then we're also What we're gonna also want to do is we'll just make this odd Even so we're gonna use Ma division so it's gonna be turned mod to turn equals turn mod too.

And this is just basically making it go, uh, take the remainder of whatever our turn is divided by two.

So this is just gonna alternated between zero and one, so it will alternate between player one's tearing and player Tuesday.

So let's just see if this works properly.

So we're gonna run this build python current file player will make your selection to player to make your section for player one.

Make your selection to that.

Looks good.

It's alternating between our player one our player toe Cool.

Okay.

And now we're gonna want to start building our actual functionality.

You're gonna wanna be ableto make this selection right here.

Actually drop a piece and to our board.

So I want to find another function up here called definition drop piece, and we might to find a couple function, so maybe have ah drop piece and I'll just do pass for now.

Maybe we'll also have, like is valid location.

So that would check whatever number that the player typed in.

We'll check to see if that's a valid location.

We'll also define a function called Get Next Open Row, and how old these functions are gonna work together is as follows.

So it all begins with the player making a selection.

0 to 6 year represents the column that they want to drop their peace.

And so maybe a more appropriate title for this would be see a while.

Representing Column.

See you.

Well next.

Gonna take this column and the current board we have and pass it into this is valid location functions aboard.

Calm, individualized.

How we can check to see if the columnist selected is a valid location.

We will print out the board real quick.

So as you can see, imagine this is the zero throws the first row, second row all the way up to the fifth row here.

And then this is the zeroth column.

First column second column, etcetera.

We're starting at zero as our first index, so if we wanted to check if the column that the user selected.

Let's just assume that the user always types in a valid number 0 to 6.

We wanted to check to see if it's valid.

All we need to do is make sure that this top row for that specific column is not been filled.

So let's imagine that we're putting one's in for player one going and twos in for player to going.

So if this top row is still zero for the specific column we selected, then we know that it's okay for us to drop a piece in that row are in that column.

It hasn't been filled all the way to the top.

So do that.

So this is the fifth row.

That's all I'm going to do is just check to see whether or not the position at the fifth row.

And let's say, you know, whatever calling we select is zero.

And if it is, that means the calm is still free.

If it's not, then that's not of allocation.

What have the user try something else, So to do that, that's just too bored.

So we're gonna return board and then the the row is five, and the column is whatever the user selected.

So here so and we're gonna make sure that's equal equal zero.

So if that's true, then we're good to go.

We're good to let them drop the piece there.

If that's not true, then that means the column has been filled up all the way.

And one thing I'll note that will probably change in a future video is that it's kind of getting messy my coat a little bit with just throwing these random numbers here all the way all over the place.

And programming is that called magic numbers.

You kind of don't know where they come from, so I'll clean those up in some of the future videos in the series.

So Return Board five column equals equals zero.

And that is just checking to make sure that that column has an empty slot.

Okay, so now that we've gotten the valid location, let's get the next open row in that column.

So if you think back to our board, that's just checking to see when we drop it in that, say, the zeroth column here on the left, checking to see which row of these the piece will fall on.

So to do this.

We're gonna write a quick little loop so we're going to do for and we're gonna start the past in the board in the column into this one.

So the loop we're gonna right here is for are in range and I'm actually gonna start Ah, getting rid of some of these magic numbers.

So I'm gonna initialize a global Vario called ro count.

And often Global's are capitalized just to serve that are static variables that don't change or capitalize just to show that they're non changing variable.

So the number of rose, we have a six, and the number of columns we have is seven.

So I'm gonna do for our Sofer row and range.

So the number of rows we have so, ro count, we're going to check the board position.

We're gonna see if board are position.

First of the column equals equals zero.

Then we want to return that row.

So basically, if the row is equal to zero, so imagine we're filling this whole board up with ones and twos.

If the slot is still zero, that means it's empty still, So we're gonna return the first instance that it's empty.

So this ours an account from zero to, uh, row count minus one.

And we're gonna return that first case where it equals zero.

Okay, so now we got the next open road, and then finally, what we're gonna want to do is drop the piece.

So this is gonna take in the board, the row and the column, and then we'll also add something.

We'll just call it the piece.

So whether it's player one or two going So all this is gonna dio is go forward row call him.

Equals equals peace.

So we're gonna make it fill in the board with whatever piece that the player just dropped.

So let's put this all together in our loop.

So first we got the column, and now we're gonna check if is valid, location of the board in the column, and then we can start getting the next MP.

Rosa Ro equals get next open row, and that takes in the board and columns.

Well, so get next time put in row board column, and then we're gonna finally drop piece.

We're taking the board, the row, the column, and then for player won the pieces.

Just the one and we're gonna copy this in to player to as well cause player one player to the functionality of what they're doing is the same.

But we'll just have to change the peace here to two.

So now and then finally after the player goes would probably want to print out the boards.