WEBVTT 00:01.260 --> 00:06.390 Let's continue talking about race, we have several functions and JavaScript, which we can use with 00:06.390 --> 00:11.220 arrays, those functions are built in and they are called as array methods. 00:12.360 --> 00:17.970 These methods make arrays more powerful and useful things in JavaScript before we actually demonstrate 00:17.970 --> 00:18.250 them. 00:18.270 --> 00:22.690 I would like to show you how we can change values dynamically in array. 00:23.310 --> 00:29.610 Let's create variable colors and insert here some colors. 00:30.590 --> 00:31.160 White. 00:32.220 --> 00:32.760 Black. 00:34.330 --> 00:35.670 And read. 00:37.980 --> 00:42.900 Generally, we can change any of the values inside a right, for example, if we want to change the 00:42.900 --> 00:49.410 value of this second item, which is blek, we can simply access on the item and assign new value with 00:49.410 --> 00:54.600 equal operator right colors and indicate the index number one. 00:55.700 --> 00:57.710 And right here, the value as great. 00:59.590 --> 01:01.480 Let's look callers in council. 01:04.940 --> 01:08.420 And you see that black is removed and it's replaced with green. 01:09.550 --> 01:16.210 All right, let's talk about methods and demonstrate how some of them work, suppose that we want to 01:16.210 --> 01:17.740 add items to array. 01:18.310 --> 01:21.060 In this case, we can use method, which is called push. 01:21.400 --> 01:23.530 It's very frequently used in JavaScript. 01:23.950 --> 01:27.230 This method adds a new element at the end of an array. 01:27.700 --> 01:28.210 So right. 01:28.210 --> 01:29.530 Color start, push. 01:31.670 --> 01:35.390 And as an argument plays here, the color blue. 01:37.340 --> 01:45.050 Reload and you see that blue color is added at the end of the right and the length of the arrow has 01:45.050 --> 01:46.670 increased and became for. 01:48.130 --> 01:54.490 OK, as we said, push method as the element at the end of the era and in order to remove elements from 01:54.490 --> 01:59.920 the and we need to use another method, which is called pop the right colors, not pop. 02:01.500 --> 02:06.450 Because of that, methods are functions, we always need to use parentheses with them. 02:07.380 --> 02:10.350 Without and you see that blue has removed. 02:11.440 --> 02:19.200 So Push Method has added the item and pop method has removed it both happened at the end of the array. 02:19.900 --> 02:25.930 All right, if we need to remove or add the items at the beginning of the array, there are two methods 02:25.930 --> 02:29.350 for doing that, which are shift and on shift. 02:29.980 --> 02:32.320 Right colors that shift. 02:34.330 --> 02:38.690 That revolt and you see that first item is removed at the beginning of the year. 02:38.790 --> 02:44.050 Right now, let's add item for that use on Shifta method, right? 02:44.050 --> 02:45.520 Colors start on shift. 02:46.580 --> 02:55.640 And as an argument, let's sit here, the Color Purple rollout, and you see that we have purple at 02:55.640 --> 02:56.780 the beginning of the year, right? 02:58.100 --> 02:58.610 All right. 02:59.750 --> 03:05.390 The next and the last method that we are going to demonstrate is index of it's very useful. 03:05.390 --> 03:11.540 And also it's frequently used this method search the array for the specified item and the returns its 03:11.540 --> 03:12.050 position. 03:12.890 --> 03:21.200 So if we want to get the index number of red color in the array, we need to write colors DOT index 03:21.200 --> 03:21.500 of. 03:22.920 --> 03:26.030 And as an argument, that's right, you're right. 03:26.080 --> 03:26.340 Call. 03:28.550 --> 03:36.680 Reload and we got to, because the index number of red color is to let's search another color, which 03:36.680 --> 03:41.450 is not actually the array change read into, for example, brown. 03:43.500 --> 03:51.330 Then reload and you see that we have minus one, it means that the color brown wasn't found in the array 03:51.720 --> 03:54.420 and the index of the returned minus one. 03:55.320 --> 03:58.800 Generally, when we use index of method, an item is not found. 03:59.070 --> 04:01.020 It always returns minus one. 04:02.150 --> 04:10.280 All right, let's demonstrate our index of method is used with a little example, I'm going to use your 04:10.280 --> 04:14.190 if statements and check if the array includes blue color, right. 04:14.210 --> 04:16.790 The condition color, state index of. 04:18.610 --> 04:24.700 That insert here, blue color triple equals two, minus one. 04:27.070 --> 04:34.540 So if this condition is true, then it means that blue color doesn't exist in the area and then I'm 04:34.540 --> 04:43.540 going to add the Mashad color using push method, the right color start, push and insert here blue, 04:44.410 --> 04:46.420 then display colors in council. 04:46.930 --> 04:47.470 Right. 04:47.470 --> 04:49.720 Cancel that log colors. 04:50.820 --> 04:57.180 Revolt and you see that blue collar is added to the array because the condition in the if statement 04:57.180 --> 04:57.900 was true. 04:59.110 --> 05:03.310 This little example shows the usefulness of the index of method. 05:04.480 --> 05:06.880 OK, it was error methods. 05:07.240 --> 05:12.640 There are lots of useful and helpful methods regarding a race which you will meet throughout the course. 05:13.710 --> 05:15.080 All right, let's move on.