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It's time for your challenge.

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You've already seen how we've managed to get the snake game

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to keep track of the high score.

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And when the user scores a number that's greater than the high score,

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then we replace that high score with the new value. But unfortunately

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as you saw previously, at the moment when we run this game and we achieve a new

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high score, the next time that we run the game again

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that is completely lost.

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So the first thing I want you to do is to right click on your project,

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create a new file and call it data.txt.

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So we're going to create a data text file.

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Now this data text file is just going to contain a single number,

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zero.

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And we're going to use the data that's in this data.txt file to keep track of

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the high score.

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And it's your job to figure out how you can convert this simple attribute here,

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high score, to instead of using a number that we've just created in the code,

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I want you to use the number that's inside data.txt.

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So you'll need to read from it here and then later on,

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you'll need to write to it when we reset the game and check

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if there is a new high score. Everything going well,

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you should be able to run the game,

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achieve a new high score and then stop and rerun the game and still see that

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high score showing up. Think about what you learned in the last lesson,

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have a think about how you can convert the text in here into a number using

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what you've learned in previous lessons and pause the video and give this

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challenge a go.

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All right.

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So we know that we've already got this file, data.txt, and it already

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contains the number zero. So instead of using this line of code,

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we're going to be reading from that file to get that zero.

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Let's delete this line of code. And instead,

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I'm going to open my file with the file name

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that is data.txt. And the file name is, of course, a string

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like you see here wrapped in quotation marks,

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and we're going to use the with keywords so that we don't have to bother about

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closing the file again.

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We can get Python to manage it for us. with opening this file,

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and I'm going to save that file to a variable called data.

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Now I'm going to use that data and read from it. Now,

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once I've read from it,

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I should end up with some sort of string that's going to represent the contents

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of this file.

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So that string will need to be converted to an integer

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if we want to use it as a number

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which we can increase and change in our game.

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So I'm going to type convert it into an integer. And then finally,

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I'm going to save that as the value for our new attribute,

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self.high_score. That's the reading part done

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and if we run our code as it is,

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it should already work as it did before,

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but it won't have the feature that we want

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which is to be able to quit out of the game,

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stop and rerun.

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So it still not saving the latest high score to that data.txt.

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You can see it's still zero. So where do we want to save it? Well,

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it's got to happen every time we adjust the high score.

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When the score is greater than the current high score,

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we set the high score to the new score. But in addition,

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we're going to read from a file data.txt.

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So let's use our syntax with,

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and then open, again, and let's pass in the name of our file, data.txt.

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And remember that we also need to change the mode to 'w' for

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write because otherwise, it's not going to let us write to that file. Now,

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once we've opened it and we've saved it as a variable called data,

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then we can write to that data using data.write.

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And what are we going to write to it? Well, we have to write a string.

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So let's use an f-string to convert our current self.high_score into a

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string, and then write that into our file, data.txt.

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Now notice what happens when I run my code.

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So I'm going to achieve a new high score of, um,

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2, which I'm very proud of. And now if I hit stop,

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take a look at data.txt. It's been updated,

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it's been rewritten by these two lines of code.

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So now if I rerun my program,

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you can see it already is showing my previous high score of 2,

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and I can keep playing this game and accumulate my high score

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and all of that data will be saved to my file

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data.txt, like that.

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So did you manage to get this right? And by the way,

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if you see this keyboard interrupt, don't worry.

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That's just because we clicked on the stop button to stop our program because it

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wants to keep on going forever until we achieve the highest score of them

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all. The point of this exercise is to try and get you to review what we learned

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in the last lesson, which is opening a file, reading the file,

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and also writing to the file and remembering the mode that we have to change.

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And hopefully, you'll start to see how this could be really useful in terms of

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improving the usability of our programs in our games.

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Now in the next lesson, we're going to talk more than just about files.

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We're going to talk about file paths and directories.

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So for all of that and more, I'll see you there.