1 00:00:00,510 --> 00:00:01,470 Welcome back. 2 00:00:01,640 --> 00:00:08,550 And this week, we are going to look at another type of operators, the comparison operators, so comparison 3 00:00:08,550 --> 00:00:10,970 operators are the ones that you can see here. 4 00:00:10,980 --> 00:00:17,250 So double equal, not equal, less than greater than less than equal or greater equal. 5 00:00:17,490 --> 00:00:20,570 So now let's see how they are used in. 6 00:00:21,600 --> 00:00:25,830 First of all, let's create this variable called is equal. 7 00:00:27,390 --> 00:00:35,610 And it's going to be the result of the following operation, which means five equal equal three. 8 00:00:36,150 --> 00:00:37,890 So what does that do? 9 00:00:38,190 --> 00:00:45,230 Well, it checks if the value on the left hand side is the same as the value on the right hand side. 10 00:00:45,480 --> 00:00:48,310 So that's what this double equal sign does. 11 00:00:48,570 --> 00:00:55,270 So it's comparing two values to each other and it's going to give us a boolean result. 12 00:00:55,290 --> 00:01:00,320 So it says it's a boolean expression, even though we can simplify the boolean expression. 13 00:01:00,330 --> 00:01:01,210 So let's just do that. 14 00:01:01,560 --> 00:01:04,920 You can say it gives me the result directly, which is false. 15 00:01:05,080 --> 00:01:10,140 But of course, that's not what I wanted, because what I wanted is to display this operation here, 16 00:01:10,350 --> 00:01:18,300 which is just saying, OK, one side equal, equal the other side or is the one side the same value 17 00:01:18,300 --> 00:01:21,720 as the other side of this equation here? 18 00:01:22,020 --> 00:01:27,090 So if you do that, you will get a result, which is either false or true. 19 00:01:27,270 --> 00:01:31,770 So if we do the same with five equals equals five, then of course the result will be true. 20 00:01:32,130 --> 00:01:36,000 And in this case, it's super obvious because we can see those values. 21 00:01:36,180 --> 00:01:42,270 But let's say they are hidden behind a variable where you can't always see the variable value, then 22 00:01:42,270 --> 00:01:49,510 this will be a very useful operation because maybe you even want to do something based on that operation. 23 00:01:50,040 --> 00:01:55,470 So let's say if this condition is true, then you want to run some code, then it's going to be very 24 00:01:55,470 --> 00:01:58,700 important to do this type of comparison operations. 25 00:01:58,950 --> 00:02:03,440 And of course, this is also something that we are going to look at later on, which are if statements. 26 00:02:03,660 --> 00:02:08,190 But for now, this is our very simple operation that we have here. 27 00:02:08,550 --> 00:02:12,630 So now let's go ahead and print something onto our console. 28 00:02:13,140 --> 00:02:19,060 And I'm going to write is equal is plus is equal. 29 00:02:19,530 --> 00:02:23,610 So what I'm doing here is I'm using concatenation. 30 00:02:24,390 --> 00:02:25,560 So it's just. 31 00:02:26,910 --> 00:02:32,230 Using this strength and then it's converting this into a string and just saying whatever the value is. 32 00:02:32,610 --> 00:02:36,640 So if we run that we can see that is equal, is false. 33 00:02:37,140 --> 00:02:39,270 So our is equal, is false. 34 00:02:39,540 --> 00:02:46,920 So then, of course, our idee, which means our Android studio says, hey, you can convert concatenation 35 00:02:46,920 --> 00:02:47,660 to a template. 36 00:02:47,670 --> 00:02:48,560 So let's do that. 37 00:02:48,570 --> 00:02:50,130 And you can see what it does. 38 00:02:50,460 --> 00:02:55,710 It changes this to having a very different way of writing it. 39 00:02:56,070 --> 00:03:01,840 So one was the concatenation, and this one is a template that we're using here, which requires this 40 00:03:01,890 --> 00:03:02,610 dollar sign. 41 00:03:03,060 --> 00:03:10,380 So what we can do is we can use this dollar sign and afterwards, whatever the value or the variable 42 00:03:10,380 --> 00:03:13,560 that we want to use is, will be printed here. 43 00:03:14,130 --> 00:03:17,800 So in this case, it's just going to be the result of whatever we had here. 44 00:03:17,820 --> 00:03:20,340 So if we run, this will result in the same. 45 00:03:21,520 --> 00:03:23,750 Type of print statement that we have here. 46 00:03:23,800 --> 00:03:27,640 So I need to run it twice and we are is equal, is false. 47 00:03:28,450 --> 00:03:34,600 So now let's use this a little more, because let's create a another comparison. 48 00:03:34,990 --> 00:03:41,670 Where I'm just going to create is not equal is going to be five, not equal five. 49 00:03:41,680 --> 00:03:45,040 So let's just test if that is true or false. 50 00:03:45,070 --> 00:03:48,250 Of course, it's going to be false because five is equal. 51 00:03:48,250 --> 00:03:48,700 Five. 52 00:03:49,390 --> 00:03:56,710 But if we just print that now and let me put it this again, but now with is not equal. 53 00:03:57,520 --> 00:03:57,910 All right. 54 00:03:57,910 --> 00:04:01,480 So now I'm using is not equal instead of is equal. 55 00:04:01,690 --> 00:04:08,110 And I'm going to comment this line out and I'm going to change the name here as well. 56 00:04:08,120 --> 00:04:10,870 So it's going to be is not equal is. 57 00:04:11,020 --> 00:04:12,850 And then let's see if it's true or false. 58 00:04:13,120 --> 00:04:17,200 And we can see this is not equal, is false because five is equal. 59 00:04:17,200 --> 00:04:20,220 Five, but we are checking if five is not equal five. 60 00:04:20,230 --> 00:04:25,220 So this exclamation mark here says that it should be not equal. 61 00:04:25,360 --> 00:04:30,360 So this year is another way of testing a comparison. 62 00:04:30,700 --> 00:04:33,460 But of course, there are a bunch more that we have here. 63 00:04:33,700 --> 00:04:37,700 So what we can check is, let's say the following. 64 00:04:37,780 --> 00:04:43,450 So instead of creating a new variable for every single one of those comparison operators, let's just 65 00:04:43,450 --> 00:04:45,560 do it in the print line statement directly. 66 00:04:45,850 --> 00:04:46,330 So. 67 00:04:47,680 --> 00:04:58,420 Is greater, so this case is five greater three is going to be and now I'm using something very cool 68 00:04:58,420 --> 00:05:06,370 here because I'm using another pretty cool feature here of Kotlin, where we have the same principle 69 00:05:06,370 --> 00:05:07,210 that we had here. 70 00:05:07,390 --> 00:05:14,620 But now because we don't just have one variable that we want to put into a string, but we want to put 71 00:05:14,620 --> 00:05:19,030 a calculation, so to speak, or in this case, a comparison. 72 00:05:19,460 --> 00:05:24,670 So that whole expression, so to say, and then we need to use these curly brackets. 73 00:05:24,680 --> 00:05:31,450 So we're saying, please run the code within the curly brackets and then print the result in the stead. 74 00:05:31,510 --> 00:05:33,740 So at this spot of our code. 75 00:05:34,450 --> 00:05:35,920 So now if we run this. 76 00:05:37,680 --> 00:05:42,070 We can see that it says is five crater three is true. 77 00:05:42,210 --> 00:05:46,100 Well, of course it's true because five is a greater number than three years. 78 00:05:46,800 --> 00:05:50,190 But now let's say we check the same thing with a minus five. 79 00:05:50,700 --> 00:05:56,040 If that is greater than three, then it should be false and that we are just false. 80 00:05:56,070 --> 00:05:59,320 Of course, I didn't add the minus here in the print statement. 81 00:05:59,700 --> 00:06:00,000 All right. 82 00:06:00,000 --> 00:06:01,980 But get the gist of it now. 83 00:06:02,390 --> 00:06:06,090 Of course, we can do the same with some other print statements here. 84 00:06:06,090 --> 00:06:13,290 So print 11 is five, lower equal three. 85 00:06:14,520 --> 00:06:18,120 And then please try to do the expression in here. 86 00:06:18,390 --> 00:06:20,940 So try it yourself before I will show you how to. 87 00:06:22,320 --> 00:06:30,690 All right, so the expression starts with a curly bracket and then we say five less than equal three. 88 00:06:31,810 --> 00:06:38,560 All right, so this is the expression now let's see what we get as a result here and we can see is five 89 00:06:38,560 --> 00:06:43,490 lower equal three it says false because five is a greater number than three. 90 00:06:43,690 --> 00:06:45,580 So the whole expression. 91 00:06:46,480 --> 00:06:51,170 Ends up being false, and that's what we get as the print statement here. 92 00:06:51,760 --> 00:06:56,620 So this concept that we use here is called string interpolation. 93 00:06:56,860 --> 00:06:57,250 All right. 94 00:06:57,260 --> 00:07:05,290 So just so you have seen this keyword, of course, you can now go ahead and do the same with the other 95 00:07:05,620 --> 00:07:08,590 comparison operators that we've seen there at the top. 96 00:07:08,620 --> 00:07:20,140 So instead, we can use Krater equal and here is higher or greater equal three. 97 00:07:20,740 --> 00:07:21,550 And then. 98 00:07:22,740 --> 00:07:24,000 We saw the other one, right? 99 00:07:24,420 --> 00:07:25,140 I actually. 100 00:07:27,420 --> 00:07:28,020 Is. 101 00:07:28,950 --> 00:07:29,550 Les. 102 00:07:30,560 --> 00:07:31,040 Three. 103 00:07:32,530 --> 00:07:33,670 And I let's to run this. 104 00:07:35,370 --> 00:07:38,630 So now we have all of our results here. 105 00:07:40,670 --> 00:07:43,900 Is not equal this false or is minus five? 106 00:07:43,940 --> 00:07:49,880 Less than three, it's true, of course, because a negative value is going to be less than a positive 107 00:07:49,880 --> 00:07:57,080 value than we have is lower or five lower equal three is false and is five greater equal. 108 00:07:57,080 --> 00:07:58,100 Three is true. 109 00:07:58,710 --> 00:08:04,580 Of course, we can also set a five in there just to see if this is still going to work. 110 00:08:06,190 --> 00:08:09,830 And once we run it, we can see is five greater equal? 111 00:08:09,850 --> 00:08:13,340 Five is also true because five is equal, five. 112 00:08:13,360 --> 00:08:15,490 That's why this equation is correct. 113 00:08:15,700 --> 00:08:19,880 So this greater equal is accepting both. 114 00:08:20,080 --> 00:08:26,140 So it's going to return true if the left value is greater than the right value or if they are equal. 115 00:08:26,920 --> 00:08:27,250 All right. 116 00:08:27,250 --> 00:08:29,140 So that's it for assignment operators. 117 00:08:29,320 --> 00:08:33,850 And the next video, we are going to check out increment and decrement operators. 118 00:08:33,880 --> 00:08:34,690 So see their.