WEBVTT 1 00:00:01.290 --> 00:00:05.633 And now, it's time for coding challenge number three. 2 00:00:07.380 --> 00:00:08.970 And we are still working 3 00:00:08.970 --> 00:00:11.700 on our football betting application. 4 00:00:11.700 --> 00:00:15.850 Now this time, we have this map down here. 5 00:00:15.850 --> 00:00:19.590 So this one, which contains all the events that happened 6 00:00:19.590 --> 00:00:21.360 during the game. 7 00:00:21.360 --> 00:00:24.370 So the values here are the events themselves, 8 00:00:24.370 --> 00:00:27.680 for example, a goal or a substitution, 9 00:00:27.680 --> 00:00:31.833 and the keys are the minutes, in which the event occurs. 10 00:00:32.790 --> 00:00:37.270 And just notice, that a football game has 90 minutes, 11 00:00:37.270 --> 00:00:39.180 plus some extra time. 12 00:00:39.180 --> 00:00:41.650 So this might be a little bit over 90, 13 00:00:41.650 --> 00:00:43.980 but usually it's always 90 minutes, 14 00:00:43.980 --> 00:00:47.563 in case you're not familiar with this beautiful game. 15 00:00:48.630 --> 00:00:53.020 Anyway, your tasks are to create an array called events, 16 00:00:53.020 --> 00:00:55.410 which will contain all the different game events 17 00:00:55.410 --> 00:00:57.830 that happened during this game. 18 00:00:57.830 --> 00:01:00.983 And that means no duplicates in that array. 19 00:01:01.960 --> 00:01:03.970 Now, after the game has finished, 20 00:01:03.970 --> 00:01:08.970 it was found that the yellow card from minute 64 was unfair. 21 00:01:09.050 --> 00:01:12.810 So please just remove this event from the log. 22 00:01:12.810 --> 00:01:16.260 Next up print dis string to the console. 23 00:01:16.260 --> 00:01:19.000 An event happened on average every nine minutes. 24 00:01:19.000 --> 00:01:23.890 And of course, your task is to calculate this nine minutes, 25 00:01:23.890 --> 00:01:27.473 keeping in mind, that a game has 90 minutes. 26 00:01:28.440 --> 00:01:31.380 Finally, loop over the events, 27 00:01:31.380 --> 00:01:33.320 and then log into the console. 28 00:01:33.320 --> 00:01:36.180 And what's tricky about this, is that you should mark 29 00:01:36.180 --> 00:01:39.010 whether they happened in the first half of the game, 30 00:01:39.010 --> 00:01:40.740 or the second half. 31 00:01:40.740 --> 00:01:43.130 And the second half means, 32 00:01:43.130 --> 00:01:46.003 that it happened after 45 minutes. 33 00:01:46.990 --> 00:01:49.123 So it should look something like this. 34 00:01:50.380 --> 00:01:53.380 So I believe that this challenge is a little bit easier 35 00:01:53.380 --> 00:01:54.760 than the previous one, 36 00:01:54.760 --> 00:01:57.570 and so hopefully you can manage to complete 37 00:01:57.570 --> 00:01:59.320 all of these four tasks. 38 00:01:59.320 --> 00:02:01.463 line:15% So I'll see you once you're done. 39 00:02:05.670 --> 00:02:09.160 So, I hope that was fun. 40 00:02:09.160 --> 00:02:12.540 So let's get started immediately with the solution here. 41 00:02:12.540 --> 00:02:16.380 So we should create an array called events, 42 00:02:16.380 --> 00:02:18.720 with the unique events. 43 00:02:18.720 --> 00:02:23.720 So basically, that's the unique values of all of these here. 44 00:02:24.460 --> 00:02:27.100 Now, what are these values here? 45 00:02:27.100 --> 00:02:31.270 They are essentially the values of this map, right? 46 00:02:31.270 --> 00:02:34.660 So, what I'm saying, is that they are 47 00:02:34.660 --> 00:02:39.660 in gameEvents.values. 48 00:02:40.020 --> 00:02:42.010 And we learned about this one 49 00:02:42.010 --> 00:02:44.893 kind of by the end of the last video. 50 00:02:46.870 --> 00:02:49.070 So let's comment out this one here. 51 00:02:49.070 --> 00:02:52.820 And so indeed, we see that this is what contains 52 00:02:52.820 --> 00:02:55.733 the values that we are interested in. 53 00:02:57.260 --> 00:02:58.093 Alright. 54 00:02:59.130 --> 00:03:02.713 So, let's say gameEvents.values, 55 00:03:05.280 --> 00:03:07.510 and this is our starting point, 56 00:03:07.510 --> 00:03:09.870 and now to get the unique values here, 57 00:03:09.870 --> 00:03:14.690 we basically need to create a set, out of this, right? 58 00:03:14.690 --> 00:03:17.183 That's the main use case of sets. 59 00:03:18.580 --> 00:03:23.480 So, new set, but this alone is not going to be enough, 60 00:03:23.480 --> 00:03:24.963 but let's still take a look, 61 00:03:27.860 --> 00:03:28.923 at this for now, 62 00:03:30.760 --> 00:03:32.370 and beautiful. 63 00:03:32.370 --> 00:03:34.770 So, indeed we have a set with the only 64 00:03:34.770 --> 00:03:37.450 four events that happened. 65 00:03:37.450 --> 00:03:40.890 So, there were only goals, substitutions yellow cards 66 00:03:40.890 --> 00:03:42.083 and red cards. 67 00:03:43.030 --> 00:03:47.330 And now to convert us to an array, we do adjust like before. 68 00:03:47.330 --> 00:03:49.090 Create a new array, 69 00:03:49.090 --> 00:03:53.270 and a spread operator to unpack this set, 70 00:03:53.270 --> 00:03:54.863 and then we are done. 71 00:03:56.960 --> 00:04:01.310 Next up, this one is the easiest one, 72 00:04:01.310 --> 00:04:05.963 so it tells us to delete the event from minute 64. 73 00:04:06.900 --> 00:04:09.090 So that's very easy. 74 00:04:09.090 --> 00:04:13.460 So gameEvents.delete, 75 00:04:13.460 --> 00:04:17.530 and now all we have to do is to use that exact key, 76 00:04:17.530 --> 00:04:20.350 and then that event will be gone. 77 00:04:20.350 --> 00:04:24.343 Great. The next one is just as easy I believe. 78 00:04:26.550 --> 00:04:28.903 So let's just grab this from here. 79 00:04:33.757 --> 00:04:38.257 And now we just need to calculate this actual average. 80 00:04:39.150 --> 00:04:40.463 And how do we do that? 81 00:04:41.640 --> 00:04:46.640 So basically, to say that an event happened every X minutes, 82 00:04:47.160 --> 00:04:51.320 we simply need to divide the number of events by 90 minutes. 83 00:04:51.320 --> 00:04:52.923 So the duration of the game. 84 00:04:54.050 --> 00:04:54.910 So, we see here 85 00:04:54.910 --> 00:04:59.910 that we have three, six, nine, eleven events. 86 00:05:00.110 --> 00:05:02.993 So, how can we count that programmatically? 87 00:05:04.120 --> 00:05:07.840 line:15% Well, for that we have gameEvents.size, remember? 88 00:05:11.510 --> 00:05:15.150 line:15% And now we just divide that by 90, 89 00:05:15.150 --> 00:05:18.730 line:15% and with that, we get this weird number 90 00:05:18.730 --> 00:05:22.480 line:15% and that's because in fact we need the opposite. 91 00:05:22.480 --> 00:05:23.660 line:15% So we need to say 92 00:05:23.660 --> 00:05:28.660 line:15% 90 minutes divided by how many events there happened, 93 00:05:29.620 --> 00:05:31.640 line:15% to say that on average, 94 00:05:31.640 --> 00:05:33.663 line:15% something happened every nine minutes. 95 00:05:35.040 --> 00:05:38.050 Now, if we want it to be really specific, 96 00:05:38.050 --> 00:05:41.630 then this game actually lasted 92 minutes. 97 00:05:41.630 --> 00:05:44.183 So, how do we get that value? 98 00:05:46.560 --> 00:05:48.770 So this is just a bonus, Okay? 99 00:05:48.770 --> 00:05:52.310 I didn't expect you to do this one. 100 00:05:52.310 --> 00:05:55.150 So this 92, is essentially the last 101 00:05:55.150 --> 00:05:57.193 of the keys of the map. 102 00:05:58.450 --> 00:06:00.560 I'm sold. Let's get the keys. 103 00:06:00.560 --> 00:06:05.490 line:15% So, that's gameEvents.keys. 104 00:06:05.490 --> 00:06:09.033 And as always, we need to convert this to an array. 105 00:06:11.500 --> 00:06:13.943 line:15% So, using all the tools that we already learned. 106 00:06:16.040 --> 00:06:17.393 line:15% So just to make sure, 107 00:06:19.580 --> 00:06:21.270 line:15% indeed it is. 108 00:06:21.270 --> 00:06:23.880 And now we want the last value. 109 00:06:23.880 --> 00:06:26.270 And how can we get the last value? 110 00:06:26.270 --> 00:06:28.210 Do you remember that? 111 00:06:28.210 --> 00:06:31.180 Well, we can use the pop method. 112 00:06:31.180 --> 00:06:34.440 And in the past, we mainly used the pop method, 113 00:06:34.440 --> 00:06:37.540 to simply delete the last element of the array. 114 00:06:37.540 --> 00:06:39.690 But also, back then I told you, 115 00:06:39.690 --> 00:06:42.743 that it also returns, that deleted array. 116 00:06:43.880 --> 00:06:46.280 Or actually that deleted element. 117 00:06:46.280 --> 00:06:49.860 And so, here we can take the advantage of that. 118 00:06:49.860 --> 00:06:52.500 line:15% So, this here is an array now, 119 00:06:52.500 --> 00:06:54.883 line:15% and so on that, we can call pop. 120 00:06:56.340 --> 00:06:59.640 line:15% And so that will take, the last element out of the array 121 00:06:59.640 --> 00:07:00.693 line:15% and give it to us. 122 00:07:01.640 --> 00:07:03.100 line:15% So that's 92. 123 00:07:03.100 --> 00:07:05.253 And so to make this really accurate, 124 00:07:07.180 --> 00:07:10.293 here we can now say, time. 125 00:07:12.890 --> 00:07:16.710 line:15% Okay. And so this, is even better right now, 126 00:07:16.710 --> 00:07:19.850 but again, this is just kind of a bonus 127 00:07:19.850 --> 00:07:23.090 just to show you some more nice little tricks. 128 00:07:23.090 --> 00:07:27.013 Anyway. Now our goal is to loop through the object, 129 00:07:28.510 --> 00:07:30.073 or actually through the map. 130 00:07:34.130 --> 00:07:37.683 And so this is pretty standard now at this point. 131 00:07:40.740 --> 00:07:42.573 Here we are missing the off. 132 00:07:43.500 --> 00:07:46.810 So just like we did in the last video, 133 00:07:46.810 --> 00:07:50.880 and now all we need to do, is to figure out the half. 134 00:07:50.880 --> 00:07:53.823 So if it's the first half, or the second half. 135 00:07:56.050 --> 00:07:59.490 So, what we want to lock to the console is this. 136 00:07:59.490 --> 00:08:02.163 And then so, either a first or second half, 137 00:08:06.230 --> 00:08:07.523 and then the minute, 138 00:08:08.370 --> 00:08:09.593 I believe, let's see. 139 00:08:10.580 --> 00:08:14.423 Yeah. So, the minute and then colon, and then the event. 140 00:08:15.800 --> 00:08:18.860 So let's actually make these here more specific, 141 00:08:18.860 --> 00:08:21.710 so a minute and event. 142 00:08:21.710 --> 00:08:23.760 So that makes it easier to read the code. 143 00:08:25.910 --> 00:08:29.313 So minute and event. 144 00:08:30.280 --> 00:08:33.803 And now here, let's just again, create an external variable, 145 00:08:34.730 --> 00:08:36.380 which I'm going to call the Half. 146 00:08:41.170 --> 00:08:44.210 And let's use the turnery operator here again, 147 00:08:44.210 --> 00:08:48.683 so if the minute is below or equal 45, 148 00:08:50.520 --> 00:08:54.300 then it is the first, 149 00:08:54.300 --> 00:08:57.393 otherwise it's the second, 150 00:08:59.030 --> 00:09:00.680 and that's it. 151 00:09:00.680 --> 00:09:04.753 And, that worked just fine once again. Okay. 152 00:09:07.130 --> 00:09:09.620 So, I hope that made sense, 153 00:09:09.620 --> 00:09:13.010 in case it didn't, then it's always just analyze the code, 154 00:09:13.010 --> 00:09:17.970 or you can also just ask some questions in the Q and A area. 155 00:09:17.970 --> 00:09:21.630 Anyway, we're now almost done with this section. 156 00:09:21.630 --> 00:09:25.550 Next up, all we have left to do is to work with strengths, 157 00:09:25.550 --> 00:09:28.990 which is also a really nice and really interesting topic 158 00:09:28.990 --> 00:09:31.930 that we need in JavaScript all the time. 159 00:09:31.930 --> 00:09:34.783 So make sure to follow me there, right away.