1 00:00:00,750 --> 00:00:02,950 Hello and welcome to this lecture. 2 00:00:03,000 --> 00:00:12,210 In this lecture be showing you how to use comments with your ruby code command comments can be useful 3 00:00:12,210 --> 00:00:16,750 for a variety of reasons they can be used to explain your code. 4 00:00:16,860 --> 00:00:21,740 Comments are also ignored when the code executes or runs. 5 00:00:21,750 --> 00:00:26,750 Comments can be used for trouble shooting and testing. 6 00:00:26,750 --> 00:00:30,260 Key is for testing and also for troubleshooting. 7 00:00:30,270 --> 00:00:38,580 There are two types of comments you've got a single line comment and also a mauti line comment to illustrate 8 00:00:38,580 --> 00:00:40,520 how comments are used. 9 00:00:40,530 --> 00:00:48,560 I got my text open so I'm just going to first force feed this far as it would be far too far. 10 00:00:48,890 --> 00:00:56,970 As I now see it inside my documents are a core and it's comments 11 00:00:59,370 --> 00:01:09,060 to dot are we have already got a fire call comments I just made his comments to be a big C so I'm just 12 00:01:09,060 --> 00:01:15,350 going to write some commands here first to be going to be put them for 7. 13 00:01:15,610 --> 00:01:22,240 I am going to do a puts together and when I say hello world or something. 14 00:01:24,270 --> 00:01:25,080 Well. 15 00:01:25,430 --> 00:01:26,030 Ah right. 16 00:01:26,040 --> 00:01:26,620 I'm going to do. 17 00:01:26,640 --> 00:01:36,480 I'm just going to copy this code and pasted down here just to save some time and change some techs here. 18 00:01:36,480 --> 00:01:43,710 Just say thanks for watching. 19 00:01:46,710 --> 00:01:50,860 K. And I changed it to 7 for it. 20 00:01:50,980 --> 00:01:55,060 All right so how do you use a single line comment. 21 00:01:55,080 --> 00:01:57,220 There are several ways you can use a comet. 22 00:01:57,280 --> 00:02:04,200 You can put a comment that's just the top before the code so if there for example I wanted to explain 23 00:02:04,200 --> 00:02:08,140 something about this code I'll use a single line comment. 24 00:02:08,190 --> 00:02:13,880 The symbol is that just a hash tag voicing a line comment and then I can write the comment. 25 00:02:13,890 --> 00:02:16,380 I can see hoods 26 00:02:18,580 --> 00:02:27,480 introduces or put in place if a single 27 00:02:29,700 --> 00:02:32,230 line carry. 28 00:02:33,870 --> 00:02:36,240 Return. 29 00:02:42,340 --> 00:02:43,630 Output. 30 00:02:43,670 --> 00:02:52,580 So what this is saying basically when you run this command to our fate has put this number to also leave 31 00:02:52,720 --> 00:02:56,780 a space underneath basically what is so loose. 32 00:02:56,840 --> 00:03:04,080 A comment this way it does actually interfere with the code everything the commands will still work. 33 00:03:04,430 --> 00:03:12,920 However if you decide to place a comment in front of the actual command like so then that means this 34 00:03:12,920 --> 00:03:16,460 command will not run when the code executes. 35 00:03:16,760 --> 00:03:21,740 Okay I'll do the because when the code execute comments are ignored. 36 00:03:21,740 --> 00:03:26,320 So if you persist in their comments you don't want the code that affected your players to comment. 37 00:03:26,360 --> 00:03:28,670 But for the record like I've done here. 38 00:03:28,900 --> 00:03:34,350 So if I want to switch let's put this copy this a few times. 39 00:03:35,160 --> 00:03:38,980 Maybe there's more to Paul lying comments. 40 00:03:39,110 --> 00:03:40,480 Put another one there. 41 00:03:40,670 --> 00:03:41,670 Okay. 42 00:03:42,020 --> 00:03:48,230 So if I wanted if I had several lines of code and wanted to comment everything from that line. 43 00:03:48,440 --> 00:03:55,330 So rather than use a single line only Twan I can multiple comment then I just took a course to and you 44 00:03:55,330 --> 00:03:56,670 type in biggie. 45 00:03:56,720 --> 00:04:03,720 You have to see when it begins and you have to also tell it when it ends and the do equals it. 46 00:04:04,140 --> 00:04:07,170 It is very important he is it begin and end. 47 00:04:07,280 --> 00:04:14,610 So if I execute this code the only thing I expect to be outputted on the screen is this one is 7 for 48 00:04:14,620 --> 00:04:16,520 7 and businesses. 49 00:04:16,520 --> 00:04:17,650 Hello world. 50 00:04:17,660 --> 00:04:26,120 This will be ignored and this free line of code also be ignored so let me say that and let me run to 51 00:04:26,120 --> 00:04:28,570 run that I need to open up my command prompt. 52 00:04:28,690 --> 00:04:39,290 I am going to use guitar bass command line which is this and I am going to type in the name of off so 53 00:04:39,290 --> 00:04:42,930 to read the far and I'm just going to change territory to where I sit. 54 00:04:43,010 --> 00:04:48,950 I saved it in mind documents folder and the name of the cards calls comments too. 55 00:04:48,950 --> 00:04:53,630 So I'm going to use Ruby to interact thus far by calling the name. 56 00:04:53,730 --> 00:05:01,540 I see Ruby followed by the name on the far comments to dot RB and the press enter. 57 00:05:01,600 --> 00:05:03,080 You can see this. 58 00:05:03,260 --> 00:05:04,120 You can see the code. 59 00:05:04,130 --> 00:05:12,740 Now if I open up my text editor I just want to minimize that so you can see which parts of the code 60 00:05:12,740 --> 00:05:17,270 was executed and which part didn't execute. 61 00:05:17,300 --> 00:05:21,430 So you can see the puts 747 that one executed. 62 00:05:21,880 --> 00:05:24,110 He can see the Heller was executed. 63 00:05:24,110 --> 00:05:26,070 The other three dozen lists lie. 64 00:05:26,090 --> 00:05:27,430 One two three. 65 00:05:27,500 --> 00:05:30,510 And this did not because they all being commented out. 66 00:05:30,680 --> 00:05:38,210 So that's basically how you use comments in Ruby it's going to be very important as you get more acquainted 67 00:05:38,240 --> 00:05:42,610 with the Ruby language you're going to be using to use comments a lot. 68 00:05:42,740 --> 00:05:43,340 So that's it. 69 00:05:43,340 --> 00:05:44,310 Thanks for watching. 70 00:05:44,320 --> 00:05:44,980 Bye for now.