WEBVTT 00:00.080 --> 00:00.560 Hi everyone. 00:00.560 --> 00:01.850 Welcome back to this tutorial. 00:01.850 --> 00:08.180 In this tutorial we will code and learn the map two Object map to long and map to double function as 00:08.180 --> 00:10.040 part of the streams API. 00:10.070 --> 00:12.500 The first one is map to object. 00:12.500 --> 00:17.180 This is used to convert each element in the numeric stream to some object. 00:17.540 --> 00:22.580 Don't worry, if this doesn't make sense, we'll be able to understand when we actually code this in 00:22.580 --> 00:23.210 a moment. 00:23.630 --> 00:25.220 The next one is map to long. 00:25.250 --> 00:29.270 This is used to convert a numeric stream to a long stream. 00:29.270 --> 00:30.530 Let's say you have a in stream. 00:30.530 --> 00:35.060 If you want to convert that to a long stream, you just have to call this method that is going to take 00:35.060 --> 00:37.880 care of converting that in stream to a long stream. 00:38.810 --> 00:40.040 The next one is map to double. 00:40.040 --> 00:43.790 This is used to convert a numeric stream to a double stream. 00:43.940 --> 00:48.480 We discussed this example already, but I would like to cover this again as part of this tutorial. 00:48.500 --> 00:49.970 Let's go ahead and code this one. 00:50.900 --> 00:52.790 I have the previous examples still here. 00:52.790 --> 00:58.130 I'm going to close this and create a brand new class for this tutorial. 00:58.580 --> 00:59.750 Let me close this one. 01:01.260 --> 01:01.750 This console. 01:02.170 --> 01:07.060 Now we will create a class called Numeric 01:09.040 --> 01:12.520 Stream Map example. 01:14.170 --> 01:17.410 Let's make this class executable by adding public static void main method. 01:21.120 --> 01:24.630 The first method that we are going to explore is map to object. 01:24.780 --> 01:32.610 I'm going to create public static void map to object is a method that we are going to explore. 01:32.640 --> 01:39.990 The first step is I'm going to create a stream dot range and empty range closed. 01:40.380 --> 01:42.020 I'm going to give the value as five. 01:42.030 --> 01:45.510 So it's going to have it's going to create an stream of five elements. 01:45.810 --> 01:50.760 I want to use the map to object method, as you see here, the map to object method. 01:50.760 --> 01:54.030 It takes in an INT function as an input. 01:54.060 --> 01:59.640 So our goal is going to be we are going to take this value. 02:00.930 --> 02:04.980 And then we are going to return a new integer. 02:06.030 --> 02:06.830 Return. 02:06.840 --> 02:08.160 New integer. 02:09.090 --> 02:11.820 And then I'm going to pass the value here. 02:13.330 --> 02:20.440 So in the place of New Integer, if we have any custom object, we can still use it. 02:20.440 --> 02:25.300 But the input for that custom object is going to be this integer. 02:25.300 --> 02:29.620 And after that, what I'm going to do, I'm going to do a collect of. 02:30.350 --> 02:30.740 List. 02:34.350 --> 02:39.690 And I'm going to do a static import of collector, as you see here, the static import of collector. 02:39.690 --> 02:42.180 I'm going to return this return. 02:42.180 --> 02:42.660 What is that? 02:42.660 --> 02:43.260 It is returning. 02:43.260 --> 02:46.110 It is returning a list of integer. 02:46.410 --> 02:47.790 That's what it is going to return. 02:48.450 --> 02:49.230 There you go. 02:49.890 --> 02:50.410 Sounds good. 02:50.430 --> 02:52.770 Let's call this method and print the result. 02:54.180 --> 02:57.300 So I'm going to name this one as map to object. 02:58.680 --> 03:03.090 And then let's call this let's run this example. 03:03.090 --> 03:04.530 I'm going to run this example. 03:05.910 --> 03:07.140 Then as I run the example. 03:07.140 --> 03:07.770 There you go. 03:07.770 --> 03:14.940 So we have successfully used the map to object to convert a int stream to a list of integers. 03:14.940 --> 03:19.800 So in the place of integer, if you have any custom class that just takes in an int as an input and 03:19.800 --> 03:22.620 then creates a object, you can go ahead and use this one. 03:23.400 --> 03:26.940 And the next one is we are going to explore the map too long. 03:27.870 --> 03:33.330 Public static want to create the method with void will change the return type. 03:33.330 --> 03:38.280 After we code our use case completely, it's going to be map to long. 03:39.930 --> 03:42.210 So again, I'm going to use a in stream. 03:42.300 --> 03:43.430 There we go. 03:43.440 --> 03:48.990 And here we're going to use the map to long method in the map to long method. 03:49.020 --> 03:53.310 Basically, you're going to accept an input and return the same input. 03:54.600 --> 03:57.620 And it is going to perform. 03:57.630 --> 04:02.150 I'm going to do a sum sum of all the numbers. 04:02.160 --> 04:04.320 So this one will convert. 04:08.470 --> 04:11.050 In stream to long stream. 04:12.760 --> 04:17.710 If you go to this map to long method, you can see the return type of that method is long stream. 04:17.830 --> 04:21.790 The input that it accepts is the I value that is being passed from here. 04:22.180 --> 04:30.490 This is a in stream and I value is passed from the end string. 04:31.570 --> 04:32.140 There we go. 04:32.320 --> 04:35.650 And what we are going to do, we are going to return this. 04:37.800 --> 04:39.900 Going to be long. 04:41.380 --> 04:44.740 Then run this and check. 04:45.580 --> 04:47.320 Going to be mapped along. 04:48.040 --> 04:48.940 Mapped along. 04:49.770 --> 04:50.970 Go ahead and run this one. 04:54.050 --> 04:55.190 So there you go. 04:55.280 --> 04:56.930 The result is map to long. 04:57.080 --> 05:01.070 The next method, which we are going to explore, it's going to be map to double. 05:01.100 --> 05:02.240 That's the next method. 05:03.050 --> 05:07.340 It's going to be map to double. 05:07.670 --> 05:10.910 So in the place of this, we are going to use map to double. 05:13.260 --> 05:13.530 Okay. 05:14.340 --> 05:16.290 And then the return type is going to be double. 05:16.290 --> 05:19.200 This is going to convert a in stream to. 05:20.590 --> 05:27.430 Double stream and then we are performing summation on that double value. 05:28.310 --> 05:30.220 Okay, I'm going to call this one. 05:30.370 --> 05:32.170 It's going to be map to double. 05:32.260 --> 05:36.520 And this is going to be map to double to this example. 05:38.830 --> 05:40.900 The silt is 15.0. 05:41.530 --> 05:42.670 This of type double. 05:42.870 --> 05:48.670 So this is all about map to object map to long and map to double. 05:49.150 --> 05:51.010 With this we came to the end of this tutorial. 05:51.040 --> 05:51.730 Thank you for watching.