WEBVTT 00:01.120 --> 00:06.460 In this lecture, we're going to be talking about new data structures in ethics, which are maps and 00:06.460 --> 00:12.460 sets, those new data structures can be very useful and helpful in many real world situations. 00:12.940 --> 00:18.370 At first I'm going to introduce you map actually maps to our data as key value pairs. 00:18.820 --> 00:24.850 And one of the most important things regarding maps is that we're able to store any data types as keys 00:24.850 --> 00:25.450 and values. 00:26.650 --> 00:27.070 All right. 00:27.340 --> 00:34.730 Let's demonstrate how to create maps, syntactically create variable and college map data. 00:35.480 --> 00:38.980 Actually, we need to create maps using construct annotation. 00:39.310 --> 00:44.350 For that, we have to use new operator and that the keyword map with capital letter. 00:47.080 --> 00:52.240 Let's run it in council and see what looks like right map data. 00:54.660 --> 00:56.700 Reload, and here it is. 00:57.630 --> 01:04.150 So the first thing that we see here is Sise, which actually is a prop. and it gives us the size of 01:04.150 --> 01:04.520 a map. 01:04.950 --> 01:08.050 I mean, that it indicates the number of key value pairs. 01:08.760 --> 01:11.840 It's actually like the length property of an array. 01:13.220 --> 01:18.420 If we drop down, underscore, underscore, Proteau, underscore, underscore, will find here the methods 01:18.440 --> 01:23.900 which we are able to use with maps, one of the methods that you see here is set. 01:24.500 --> 01:30.800 So at first I'm going to use it actually set method allows us to insert data into a map. 01:31.340 --> 01:43.850 So let's right map data dot set and then write inside parentheses as a key name and then as value John. 01:46.370 --> 01:54.620 Reload and see that item is added in this case, both key and value is represented as drinks, but instead 01:54.620 --> 02:00.470 of drinks, we're able to use numbers, boolean values, arrays, objects and even functions. 02:01.190 --> 02:04.940 Let's add as a key boolean value right. 02:04.950 --> 02:08.720 Map data that set right here through. 02:10.070 --> 02:11.540 And then the value, yes. 02:12.830 --> 02:17.600 Also, let's create an object, right, cost, constant object. 02:19.030 --> 02:20.980 And then added as key. 02:22.230 --> 02:26.490 Right, again, map data that set object. 02:27.520 --> 02:30.340 And then as a value right person. 02:32.360 --> 02:37.850 Reload the page and you said that we have here our newly added key value pairs. 02:38.830 --> 02:44.890 All right, in order to get the size of map, we just need to use size property using dot notation, 02:45.430 --> 02:50.560 let's run it in council duplicate and write your dot size. 02:52.800 --> 03:00.330 So here we have three, because MAP actually contains three items, so using that method is one of the 03:00.330 --> 03:01.890 ways to add items to map. 03:02.340 --> 03:10.380 But we can initialize map with data by passing an array, which itself will include other arrays with 03:10.380 --> 03:11.250 key value pairs. 03:12.060 --> 03:13.190 Let's see how it works. 03:14.010 --> 03:21.920 Open square brackets that create array with key turn and with value again. 03:22.020 --> 03:25.200 Right turn then create another array. 03:26.930 --> 03:28.100 Right is married. 03:29.820 --> 03:31.440 And the value false. 03:33.180 --> 03:37.590 Reload and you see, we have your newly added items. 03:38.760 --> 03:45.360 All right, that's actually how we add items to map and now let's see how we can get access on them 03:45.810 --> 03:46.210 for that. 03:46.230 --> 03:48.500 There is one of the methods which is called Get. 03:49.230 --> 03:52.740 So in order to get item, for example, name, we have to. 03:52.740 --> 03:53.100 Right. 03:53.970 --> 03:58.410 Cancel that log map data that get. 03:59.910 --> 04:02.070 And then the name. 04:04.830 --> 04:13.020 Reload and we have value of nine key, which is John, OK, in order to check if there exists the specified 04:13.020 --> 04:16.000 key, we can use one of the methods which is called has. 04:16.740 --> 04:21.720 So if the key exists, it returns true value, otherwise it returns false. 04:22.350 --> 04:25.470 Let's check in from updater contains object key. 04:25.470 --> 04:27.030 So write that log. 04:28.230 --> 04:30.510 Map data that has. 04:31.480 --> 04:40.650 And then insert here, object, reload, and we have to because map contains the key keep all right, 04:41.350 --> 04:48.180 besides the hazmat that we had delete, which actually allows us to delete from a single key value pairs. 04:48.760 --> 04:54.490 So, for example, if we write map data, dot delete. 04:57.220 --> 05:00.550 And indicate here one of the keys, for example, said. 05:01.510 --> 05:09.580 And as a result, you will see that with its value is removed from that, OK, in order to delete the 05:09.580 --> 05:14.960 entire data from up, we can use Carlier method, which actually will make our map empty. 05:15.430 --> 05:17.050 So that's right. 05:17.220 --> 05:19.690 Mark Dot Carlier. 05:22.120 --> 05:25.380 Then reload and I see that map is empty. 05:26.550 --> 05:28.950 All right, let's delete clear method. 05:31.410 --> 05:37.140 And if we check on the score on the score, Proteau underscore and the score we will find here for each 05:37.140 --> 05:42.240 array helper method, and I would like to note that this is the only array, Harpur, which we are able 05:42.240 --> 05:43.220 to use with maps. 05:44.160 --> 05:49.840 So that's the latest council that logs and use, for example, with map data. 05:50.350 --> 05:50.790 Right. 05:50.790 --> 05:55.340 Map DataDot forage as a first parameter. 05:55.350 --> 06:01.980 We're going to place your value because at first each method will return values of keys. 06:03.090 --> 06:06.930 And then as the second parameter that insert here key. 06:09.830 --> 06:10.820 Run in council. 06:12.860 --> 06:15.500 Value add key. 06:17.140 --> 06:25.210 Reload and we have here keys and values there was not that we were expecting, OK, besides for a chopper 06:25.210 --> 06:27.760 we can use for of statement with maps. 06:28.480 --> 06:32.350 So that's comments for each method out and then. 06:32.620 --> 06:33.700 Right for. 06:35.510 --> 06:44.420 Suppose that we want to get kids from app, so let's create let QI then use the keyboard of. 06:45.710 --> 06:50.900 In order to get all the kids from that, we have to use one of the methods of KNAB, which is called 06:50.900 --> 06:51.410 keys. 06:52.790 --> 06:55.070 So right up DataDot Keys. 06:57.900 --> 06:59.670 And that Iranian castle. 07:01.860 --> 07:03.450 Right here, keep. 07:05.020 --> 07:07.780 Let's reload the page and. 07:09.040 --> 07:15.670 You say that we have here are the keys from up in the same way we can get all the values, and for that 07:15.670 --> 07:18.580 we have to use other method, which is called values. 07:19.150 --> 07:21.460 So let's change your keys into a values. 07:23.740 --> 07:26.560 Also right value instead of key. 07:29.580 --> 07:30.180 Reload. 07:31.070 --> 07:33.200 And now we have the values. 07:34.850 --> 07:42.700 All right, if we want to get simultaneously keys and values, we can use another method which is at 07:42.710 --> 07:43.000 risk. 07:43.760 --> 07:46.100 So let's change values into entries. 07:47.280 --> 07:54.450 And also right here, instead of value array, because entries method actually returns key value pairs 07:54.450 --> 07:55.110 as a race. 07:56.170 --> 08:01.690 So let's reload and you see that we have a race which consists of key value pairs. 08:02.760 --> 08:07.710 If we don't want to get them as a race that simply we can distract you, then. 08:08.840 --> 08:17.420 So that's change arriving to key value right inside square brackets and also round them in Castle. 08:20.860 --> 08:25.360 Reload and we have now keys and values represented without a race. 08:26.530 --> 08:28.820 All right, it was all about maps. 08:28.840 --> 08:35.800 Let's go ahead and talk about another new data structure in Essex, which is set actually set holds 08:35.800 --> 08:36.940 values without keys. 08:36.940 --> 08:42.230 And mostly it's used in real world when we want to store all the unique values. 08:43.120 --> 08:44.240 Let's see what it means. 08:44.260 --> 08:46.510 I'm going to comment this code out. 08:48.400 --> 08:55.210 In order to create said, we have to use again construct a notation, let's create variable and call 08:55.210 --> 08:56.350 it set data. 08:58.270 --> 09:01.270 Then use new operator and right set. 09:03.750 --> 09:07.390 Run it in council in order to see what it actually looks like, right? 09:07.920 --> 09:08.250 Log. 09:09.270 --> 09:11.070 Set Theta. 09:13.380 --> 09:20.360 So, like Matt said, has size property as well, and if we drop down on the score on the score prior 09:20.410 --> 09:25.520 to underscore on the score, we will find here some methods that we have already seen with the map. 09:26.130 --> 09:32.400 But if you look at them carefully, you will notice that actually some of them are missing because they 09:32.400 --> 09:33.990 are not used with sets. 09:35.230 --> 09:40.530 All right, let's see how we can add items into that, we have two ways for doing that. 09:40.990 --> 09:43.290 The first one is to use add method. 09:44.080 --> 09:48.370 So if we write set data, dots add. 09:50.720 --> 09:51.980 With the value neek. 09:53.810 --> 09:54.740 That without. 09:56.500 --> 09:57.820 We will have here, Nick. 09:59.080 --> 10:05.350 Like it was in case of map, we can add as values, any data type, and you can test it on your own. 10:06.150 --> 10:13.210 The second method to add items is to place your inside parentheses array and then add as many items 10:13.210 --> 10:13.850 as we want. 10:14.770 --> 10:16.270 So that answer to your. 10:18.330 --> 10:20.160 John, that. 10:21.530 --> 10:21.950 San. 10:23.500 --> 10:25.780 Then, for example, false value. 10:27.470 --> 10:32.900 Also, place your object with property first name. 10:34.420 --> 10:34.840 Bob. 10:38.600 --> 10:44.900 And to the end, let's add here, John, once again and see what happens, reload. 10:46.290 --> 10:52.290 So we have here all the items that we have just added, but you notice that John is added here only 10:52.290 --> 10:57.450 once, that's because generally set stores only unique values. 10:58.680 --> 11:00.570 So if we check the size of that. 11:04.560 --> 11:07.140 Then we will get five. 11:08.250 --> 11:15.150 So actually, we have added six items, but because of that, we have repeated, John said, started 11:15.150 --> 11:18.660 only once, and that's why we have here five instead of six. 11:20.010 --> 11:28.530 All right, in case of sets we can use has the lead clear methods also right for a chopper, but I'm 11:28.530 --> 11:34.370 not going to waste time on that because they work in the exact same way as it was in case of maps. 11:35.520 --> 11:40.950 The last thing that I'm going to do is to use four of statement because it gives us a bit different 11:40.950 --> 11:41.420 results. 11:42.420 --> 11:48.890 So let's create for that let's value of such data. 11:49.910 --> 11:51.340 That values. 11:54.270 --> 11:56.490 That Romney town council. 12:02.280 --> 12:05.250 So if we revote, we will get values. 12:06.740 --> 12:11.270 The same will happen if we use your case method instead of values. 12:12.840 --> 12:16.110 And it happens because they actually said, doesn't have Keith. 12:17.850 --> 12:20.460 But if we use Andris method. 12:22.600 --> 12:23.650 Instead of kiss. 12:24.730 --> 12:30.140 Then we will get a raise and you see that each of these arrays contain duplicated values. 12:30.910 --> 12:36.690 Honestly, the cases of keys and interest methods are kind of weird, but that's the way how they work. 12:38.040 --> 12:44.310 All right, this was all about new data structures in year six maps and sets, I think both of them 12:44.310 --> 12:50.700 are very flexible and powerful data types, especially a map, and they can be used in many cases instead 12:50.700 --> 12:52.980 of objects and a rise in real world. 12:53.750 --> 12:57.600 Also, the key point is that they work in very simple white. 12:58.770 --> 13:00.300 OK, let's move on.