Original subtitles

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And now, it's time for coding challenge number three. 2

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And we are still working 3

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on our football betting application. 4

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Now this time, we have this map down here. 5

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So this one, which contains all the events that happened 6

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during the game. 7

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So the values here are the events themselves, 8

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for example, a goal or a substitution, 9

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and the keys are the minutes, in which the event occurs. 10

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And just notice, that a football game has 90 minutes, 11

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plus some extra time. 12

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So this might be a little bit over 90, 13

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but usually it's always 90 minutes, 14

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in case you're not familiar with this beautiful game. 15

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Anyway, your tasks are to create an array called events, 16

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which will contain all the different game events 17

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that happened during this game. 18

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And that means no duplicates in that array. 19

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Now, after the game has finished, 20

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it was found that the yellow card from minute 64 was unfair. 21

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So please just remove this event from the log. 22

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Next up print dis string to the console. 23

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An event happened on average every nine minutes. 24

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And of course, your task is to calculate this nine minutes, 25

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keeping in mind, that a game has 90 minutes. 26

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Finally, loop over the events, 27

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and then log into the console. 28

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And what's tricky about this, is that you should mark 29

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whether they happened in the first half of the game, 30

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or the second half. 31

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And the second half means, 32

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that it happened after 45 minutes. 33

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So it should look something like this. 34

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So I believe that this challenge is a little bit easier 35

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than the previous one, 36

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and so hopefully you can manage to complete 37

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all of these four tasks. 38

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So I'll see you once you're done. 39

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So, I hope that was fun. 40

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So let's get started immediately with the solution here. 41

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So we should create an array called events, 42

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with the unique events. 43

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So basically, that's the unique values of all of these here. 44

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Now, what are these values here? 45

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They are essentially the values of this map, right? 46

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So, what I'm saying, is that they are 47

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in gameEvents.values. 48

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And we learned about this one 49

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kind of by the end of the last video. 50

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So let's comment out this one here. 51

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And so indeed, we see that this is what contains 52

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the values that we are interested in. 53

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Alright. 54

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So, let's say gameEvents.values, 55

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and this is our starting point, 56

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and now to get the unique values here, 57

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we basically need to create a set, out of this, right? 58

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That's the main use case of sets. 59

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So, new set, but this alone is not going to be enough, 60

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but let's still take a look, 61

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at this for now, 62

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and beautiful. 63

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So, indeed we have a set with the only 64

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four events that happened. 65

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So, there were only goals, substitutions yellow cards 66

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and red cards. 67

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And now to convert us to an array, we do adjust like before. 68

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Create a new array, 69

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and a spread operator to unpack this set, 70

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and then we are done. 71

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Next up, this one is the easiest one, 72

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so it tells us to delete the event from minute 64. 73

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So that's very easy. 74

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So gameEvents.delete, 75

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and now all we have to do is to use that exact key, 76

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and then that event will be gone. 77

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Great. The next one is just as easy I believe. 78

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So let's just grab this from here. 79

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And now we just need to calculate this actual average. 80

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And how do we do that? 81

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So basically, to say that an event happened every X minutes, 82

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we simply need to divide the number of events by 90 minutes. 83

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So the duration of the game. 84

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So, we see here 85

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that we have three, six, nine, eleven events. 86

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So, how can we count that programmatically? 87

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Well, for that we have gameEvents.size, remember? 88

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And now we just divide that by 90, 89

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and with that, we get this weird number 90

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and that's because in fact we need the opposite. 91

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So we need to say 92

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90 minutes divided by how many events there happened, 93

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to say that on average, 94

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something happened every nine minutes. 95

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Now, if we want it to be really specific, 96

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then this game actually lasted 92 minutes. 97

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So, how do we get that value? 98

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So this is just a bonus, Okay? 99

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I didn't expect you to do this one. 100

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So this 92, is essentially the last 101

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of the keys of the map. 102

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I'm sold. Let's get the keys. 103

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So, that's gameEvents.keys. 104

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And as always, we need to convert this to an array. 105

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So, using all the tools that we already learned. 106

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So just to make sure, 107

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indeed it is. 108

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And now we want the last value. 109

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And how can we get the last value? 110

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Do you remember that? 111

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Well, we can use the pop method. 112

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And in the past, we mainly used the pop method, 113

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to simply delete the last element of the array. 114

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But also, back then I told you, 115

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that it also returns, that deleted array. 116

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Or actually that deleted element. 117

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And so, here we can take the advantage of that. 118

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So, this here is an array now, 119

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and so on that, we can call pop. 120

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And so that will take, the last element out of the array 121

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and give it to us. 122

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So that's 92. 123

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And so to make this really accurate, 124

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here we can now say, time. 125

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Okay. And so this, is even better right now, 126

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but again, this is just kind of a bonus 127

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just to show you some more nice little tricks. 128

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Anyway. Now our goal is to loop through the object, 129

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or actually through the map. 130

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And so this is pretty standard now at this point. 131

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Here we are missing the off. 132

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So just like we did in the last video, 133

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and now all we need to do, is to figure out the half. 134

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So if it's the first half, or the second half. 135

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So, what we want to lock to the console is this. 136

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And then so, either a first or second half, 137

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and then the minute, 138

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I believe, let's see. 139

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Yeah. So, the minute and then colon, and then the event. 140

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So let's actually make these here more specific, 141

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so a minute and event. 142

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So that makes it easier to read the code. 143

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So minute and event. 144

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And now here, let's just again, create an external variable, 145

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which I'm going to call the Half. 146

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And let's use the turnery operator here again, 147

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so if the minute is below or equal 45, 148

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then it is the first, 149

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otherwise it's the second, 150

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and that's it. 151

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And, that worked just fine once again. Okay. 152

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So, I hope that made sense, 153

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in case it didn't, then it's always just analyze the code, 154

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or you can also just ask some questions in the Q and A area. 155

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Anyway, we're now almost done with this section. 156

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Next up, all we have left to do is to work with strengths, 157

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which is also a really nice and really interesting topic 158

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that we need in JavaScript all the time. 159

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So make sure to follow me there, right away.