WEBVTT 0 00:00.300 --> 00:02.520 It's time for your challenge. 1 00:02.970 --> 00:05.760 You've already seen how we've managed to get the snake game 2 00:05.940 --> 00:08.160 to keep track of the high score. 3 00:08.760 --> 00:13.320 And when the user scores a number that's greater than the high score, 4 00:13.620 --> 00:18.090 then we replace that high score with the new value. But unfortunately 5 00:18.180 --> 00:23.180 as you saw previously, at the moment when we run this game and we achieve a new 6 00:23.580 --> 00:27.780 high score, the next time that we run the game again 7 00:27.840 --> 00:29.490 that is completely lost. 8 00:30.090 --> 00:34.290 So the first thing I want you to do is to right click on your project, 9 00:34.380 --> 00:38.280 create a new file and call it data.txt. 10 00:38.340 --> 00:41.280 So we're going to create a data text file. 11 00:41.880 --> 00:46.680 Now this data text file is just going to contain a single number, 12 00:47.100 --> 00:47.933 zero. 13 00:48.240 --> 00:53.240 And we're going to use the data that's in this data.txt file to keep track of 14 00:54.030 --> 00:54.863 the high score. 15 00:55.440 --> 01:00.240 And it's your job to figure out how you can convert this simple attribute here, 16 01:00.240 --> 01:05.240 high score, to instead of using a number that we've just created in the code, 17 01:06.630 --> 01:10.530 I want you to use the number that's inside data.txt. 18 01:10.770 --> 01:14.040 So you'll need to read from it here and then later on, 19 01:14.070 --> 01:18.450 you'll need to write to it when we reset the game and check 20 01:18.480 --> 01:22.800 if there is a new high score. Everything going well, 21 01:22.800 --> 01:24.330 you should be able to run the game, 22 01:24.360 --> 01:29.360 achieve a new high score and then stop and rerun the game and still see that 23 01:29.520 --> 01:33.870 high score showing up. Think about what you learned in the last lesson, 24 01:34.110 --> 01:39.110 have a think about how you can convert the text in here into a number using 25 01:40.080 --> 01:43.890 what you've learned in previous lessons and pause the video and give this 26 01:43.890 --> 01:44.723 challenge a go. 27 01:48.680 --> 01:49.100 All right. 28 01:49.100 --> 01:53.990 So we know that we've already got this file, data.txt, and it already 29 01:53.990 --> 01:58.850 contains the number zero. So instead of using this line of code, 30 01:59.180 --> 02:02.600 we're going to be reading from that file to get that zero. 31 02:03.110 --> 02:06.050 Let's delete this line of code. And instead, 32 02:06.380 --> 02:09.890 I'm going to open my file with the file name 33 02:09.890 --> 02:14.600 that is data.txt. And the file name is, of course, a string 34 02:14.630 --> 02:17.510 like you see here wrapped in quotation marks, 35 02:18.080 --> 02:21.650 and we're going to use the with keywords so that we don't have to bother about 36 02:21.860 --> 02:23.240 closing the file again. 37 02:23.450 --> 02:28.040 We can get Python to manage it for us. with opening this file, 38 02:28.100 --> 02:32.000 and I'm going to save that file to a variable called data. 39 02:32.750 --> 02:37.700 Now I'm going to use that data and read from it. Now, 40 02:37.730 --> 02:39.110 once I've read from it, 41 02:39.200 --> 02:44.200 I should end up with some sort of string that's going to represent the contents 42 02:44.810 --> 02:45.740 of this file. 43 02:46.370 --> 02:50.270 So that string will need to be converted to an integer 44 02:50.360 --> 02:52.460 if we want to use it as a number 45 02:52.730 --> 02:55.850 which we can increase and change in our game. 46 02:56.240 --> 03:01.060 So I'm going to type convert it into an integer. And then finally, 47 03:01.090 --> 03:05.320 I'm going to save that as the value for our new attribute, 48 03:05.380 --> 03:09.940 self.high_score. That's the reading part done 49 03:10.000 --> 03:12.190 and if we run our code as it is, 50 03:12.250 --> 03:15.130 it should already work as it did before, 51 03:15.460 --> 03:17.560 but it won't have the feature that we want 52 03:17.560 --> 03:21.340 which is to be able to quit out of the game, 53 03:21.700 --> 03:23.620 stop and rerun. 54 03:23.920 --> 03:28.780 So it still not saving the latest high score to that data.txt. 55 03:28.780 --> 03:33.220 You can see it's still zero. So where do we want to save it? Well, 56 03:33.220 --> 03:36.610 it's got to happen every time we adjust the high score. 57 03:37.060 --> 03:40.450 When the score is greater than the current high score, 58 03:40.690 --> 03:44.950 we set the high score to the new score. But in addition, 59 03:44.980 --> 03:47.830 we're going to read from a file data.txt. 60 03:48.130 --> 03:50.020 So let's use our syntax with, 61 03:50.260 --> 03:55.260 and then open, again, and let's pass in the name of our file, data.txt. 62 03:56.320 --> 04:01.000 And remember that we also need to change the mode to 'w' for 63 04:01.000 --> 04:05.830 write because otherwise, it's not going to let us write to that file. Now, 64 04:05.860 --> 04:10.390 once we've opened it and we've saved it as a variable called data, 65 04:10.720 --> 04:15.340 then we can write to that data using data.write. 66 04:15.850 --> 04:19.600 And what are we going to write to it? Well, we have to write a string. 67 04:19.630 --> 04:24.630 So let's use an f-string to convert our current self.high_score into a 68 04:26.260 --> 04:31.240 string, and then write that into our file, data.txt. 69 04:32.770 --> 04:36.490 Now notice what happens when I run my code. 70 04:36.490 --> 04:41.350 So I'm going to achieve a new high score of, um, 71 04:41.560 --> 04:45.670 2, which I'm very proud of. And now if I hit stop, 72 04:45.700 --> 04:48.490 take a look at data.txt. It's been updated, 73 04:48.490 --> 04:51.880 it's been rewritten by these two lines of code. 74 04:52.240 --> 04:54.760 So now if I rerun my program, 75 04:55.000 --> 05:00.000 you can see it already is showing my previous high score of 2, 76 05:00.460 --> 05:03.880 and I can keep playing this game and accumulate my high score 77 05:04.150 --> 05:07.570 and all of that data will be saved to my file 78 05:07.630 --> 05:10.450 data.txt, like that. 79 05:11.230 --> 05:14.080 So did you manage to get this right? And by the way, 80 05:14.080 --> 05:16.420 if you see this keyboard interrupt, don't worry. 81 05:16.420 --> 05:21.070 That's just because we clicked on the stop button to stop our program because it 82 05:21.070 --> 05:25.330 wants to keep on going forever until we achieve the highest score of them 83 05:25.330 --> 05:30.330 all. The point of this exercise is to try and get you to review what we learned 84 05:30.790 --> 05:34.810 in the last lesson, which is opening a file, reading the file, 85 05:35.020 --> 05:39.760 and also writing to the file and remembering the mode that we have to change. 86 05:40.360 --> 05:45.360 And hopefully, you'll start to see how this could be really useful in terms of 87 05:45.700 --> 05:50.650 improving the usability of our programs in our games. 88 05:51.850 --> 05:55.330 Now in the next lesson, we're going to talk more than just about files. 89 05:55.360 --> 05:58.810 We're going to talk about file paths and directories. 90 05:59.260 --> 06:01.810 So for all of that and more, I'll see you there.