1 00:00:00,009 --> 00:00:02,380 Let's talk about some more operators and 2 00:00:02,390 --> 00:00:05,019 starting off with the arithmetic operations. 3 00:00:05,030 --> 00:00:06,099 And this is just like, 4 00:00:06,599 --> 00:00:06,840 you know, 5 00:00:06,849 --> 00:00:12,109 the mathematics or basic mathematics that we learned back when we were kids, right? 6 00:00:12,119 --> 00:00:12,470 So 7 00:00:12,739 --> 00:00:18,709 you have, you know, one times 12 times 23 plus 1, 10 minus seven, that kind of thing, 8 00:00:18,719 --> 00:00:18,989 right? 9 00:00:19,000 --> 00:00:19,270 So 10 00:00:19,559 --> 00:00:23,340 what I've done here is I've assigned the value of 10 to variable A 11 00:00:23,540 --> 00:00:27,139 and the value of three to variable B. 12 00:00:27,329 --> 00:00:30,559 And I've written out several arithmetic operations. In here, 13 00:00:30,799 --> 00:00:35,950 we have A plus B A minus B A times B A divided by B 14 00:00:36,119 --> 00:00:38,069 A modulus B 15 00:00:38,229 --> 00:00:40,630 which will simply return the remainder 16 00:00:40,779 --> 00:00:43,259 when we divide A by B. 17 00:00:43,669 --> 00:00:50,959 And then the last one here is going to be a exponential B which will raise the value of A 18 00:00:51,299 --> 00:00:53,939 by the power of B. 19 00:00:54,060 --> 00:00:54,689 So 20 00:00:54,919 --> 00:00:56,889 what are the results here going to be? 21 00:00:56,900 --> 00:01:01,889 Let me run the program and of course, 10 plus three is 1310 minus three is 7, 22 00:01:01,900 --> 00:01:06,309 10 times three is 3010 divided by three will be 3.3333 23 00:01:06,330 --> 00:01:09,730 and then 10 with the loss three will be one. 24 00:01:09,949 --> 00:01:10,830 And of course, 25 00:01:11,080 --> 00:01:14,610 10 times 10 times 10 will be equal to 26 00:01:14,940 --> 00:01:17,449 1000 right? OK. 27 00:01:17,459 --> 00:01:22,010 So I expect that you obviously knew the answers to all of these operations. 28 00:01:22,360 --> 00:01:27,529 But let's go further, I'm going to remove this. OK? And 29 00:01:27,870 --> 00:01:30,529 I do have some more operations in here. 30 00:01:31,419 --> 00:01:32,800 And the first one in here 31 00:01:33,120 --> 00:01:37,599 is what we call an assignment operator. You can see right there, it says 32 00:01:38,029 --> 00:01:41,040 plus equals right. Let me 33 00:01:42,040 --> 00:01:43,819 add this in new lines 34 00:01:44,879 --> 00:01:46,480 and there you go. OK? 35 00:01:46,790 --> 00:01:53,940 So we have plus equals what this simply means is that we 36 00:01:54,550 --> 00:01:58,669 are going to say X equals X plus five. 37 00:01:59,169 --> 00:02:00,569 It's basically the same thing. 38 00:02:00,580 --> 00:02:06,370 So X plus equals five is, is the exact same thing as an X equals Xr plus five. 39 00:02:06,470 --> 00:02:09,210 This is just a short form of writing this. 40 00:02:09,449 --> 00:02:09,940 So 41 00:02:10,110 --> 00:02:11,990 let me just go ahead and remove this. 42 00:02:12,279 --> 00:02:14,330 So what do you think the answer here would be the answer? 43 00:02:14,339 --> 00:02:19,800 Obviously, here is going to be 15 because 10 plus five equals 15. 44 00:02:19,839 --> 00:02:24,789 Now you can do the opposite. OK? You can say minus and then equals 45 00:02:24,910 --> 00:02:30,149 the answer here obviously would be five because 10 minus five will be five 46 00:02:30,320 --> 00:02:32,809 and you have other ones of course, like the 47 00:02:33,729 --> 00:02:34,979 a multiplication 48 00:02:35,440 --> 00:02:37,830 which will give us a 50. 49 00:02:38,320 --> 00:02:40,440 And then we also have the division 50 00:02:40,600 --> 00:02:43,869 which will give us a 22 point. Oh So 51 00:02:44,000 --> 00:02:47,720 these are what we call the assignment operators. 52 00:02:47,860 --> 00:02:48,270 Now, 53 00:02:48,279 --> 00:02:51,279 I want to draw your attention to one more thing 54 00:02:51,289 --> 00:02:54,600 and this is what we call the operator precedence. 55 00:02:54,729 --> 00:02:56,190 Let me, first of all, remove 56 00:02:56,570 --> 00:02:57,789 the code 57 00:02:59,119 --> 00:03:01,580 and let me drag this to the top 58 00:03:02,589 --> 00:03:04,929 and print on a new line. 59 00:03:05,419 --> 00:03:06,679 Let me copy 60 00:03:07,100 --> 00:03:10,330 this command and come down here 61 00:03:10,720 --> 00:03:11,960 and then print. All right. 62 00:03:12,169 --> 00:03:12,649 So 63 00:03:12,789 --> 00:03:15,270 take a look at this. OK? We have two different expressions. All right. 64 00:03:15,279 --> 00:03:16,639 The first one here says 65 00:03:16,960 --> 00:03:20,050 two plus three times four. 66 00:03:20,539 --> 00:03:26,130 Well, the second one here is we have our brackets two plus three and then times four, 67 00:03:26,699 --> 00:03:30,119 what do you think the results of both expressions are going to be? 68 00:03:30,130 --> 00:03:32,889 Again, this might remind you of the math that you did back in, 69 00:03:32,949 --> 00:03:36,550 in your kindergarten or primary school days. 70 00:03:36,899 --> 00:03:39,330 But I always find this quite fascinating because 71 00:03:39,500 --> 00:03:41,649 here we're going to get two different results. 72 00:03:41,770 --> 00:03:43,679 So you can pause the video and try to 73 00:03:43,690 --> 00:03:46,750 guess what the results of both expressions would be. 74 00:03:46,990 --> 00:03:48,279 If you have your results, 75 00:03:48,750 --> 00:03:51,380 let's go ahead right now and run. 76 00:03:51,759 --> 00:03:54,179 And the first one here will be 14 77 00:03:54,339 --> 00:03:56,860 while the second will be 20. 78 00:03:57,020 --> 00:03:58,220 Why? 79 00:03:58,470 --> 00:04:01,089 Because on the first expression in here, we have two 80 00:04:01,440 --> 00:04:05,350 operators, we have the plus arithmetic operator 81 00:04:05,669 --> 00:04:07,500 and then we have the multiplication. 82 00:04:07,809 --> 00:04:13,539 Python will do the multiplication first before the addition. So 83 00:04:13,779 --> 00:04:18,980 three times four is going to be 1212 plus two is gonna be equal to 14. 84 00:04:19,269 --> 00:04:22,489 However, over here in the second expression, 85 00:04:22,790 --> 00:04:25,070 it's actually going to do 86 00:04:25,380 --> 00:04:30,579 the addition first because they're inside of brackets, 87 00:04:30,959 --> 00:04:31,779 that's why? 88 00:04:32,399 --> 00:04:35,500 So unless I'm mistaken, typically it is, 89 00:04:35,510 --> 00:04:39,779 you will have the parenthesis will be at the very top of the precedent. 90 00:04:40,070 --> 00:04:43,769 If you don't have the parenthesis, it will check for exponentiation. 91 00:04:44,119 --> 00:04:47,380 If there isn't any exponentiation, then it will go to multiplication, 92 00:04:47,470 --> 00:04:50,040 it will go to division, it will go to model loss 93 00:04:50,149 --> 00:04:52,809 addition and then finally subtraction. 94 00:04:53,339 --> 00:04:53,980 And then 95 00:04:54,250 --> 00:04:57,929 in a very complex expression, if you do have a comparison operators, 96 00:04:57,940 --> 00:04:58,700 those will come next. 97 00:04:58,709 --> 00:04:59,609 And then finally, 98 00:04:59,769 --> 00:05:01,700 logical operators, but 99 00:05:02,209 --> 00:05:04,739 no need to go any further than that over here, 100 00:05:04,929 --> 00:05:10,070 we simply have two main operators or whatever we have three, we have the parentheses 101 00:05:10,459 --> 00:05:14,450 which of course will take precedence over the multiplication. 102 00:05:14,459 --> 00:05:17,510 So two plus three is 55, multiplied by four 103 00:05:17,630 --> 00:05:21,579 equals 20. So once again, this is what we call the operator 104 00:05:21,709 --> 00:05:22,799 precedence. 105 00:05:23,260 --> 00:05:25,950 Again, to be honest, we're not really going to be working with these 106 00:05:26,589 --> 00:05:26,619 in 107 00:05:26,769 --> 00:05:30,880 this course. But nevertheless, this is something that you should be aware of. 108 00:05:30,890 --> 00:05:33,010 Thank you for watching. I will see you in the next class.