1 00:00:00,740 --> 00:00:01,550 Hey, welcome back. 2 00:00:01,550 --> 00:00:05,900 So far, you learned about instance variables and instance methods. 3 00:00:05,900 --> 00:00:11,600 And these two can also be categorized in the instance attributes category. 4 00:00:11,600 --> 00:00:15,740 So these are attributes of an instance. 5 00:00:16,520 --> 00:00:19,440 So instance variables and instance methods. 6 00:00:19,460 --> 00:00:24,420 Then you learned about class variables and class methods. 7 00:00:24,440 --> 00:00:28,520 These two are also known as class attributes. 8 00:00:28,970 --> 00:00:29,210 Right. 9 00:00:29,210 --> 00:00:33,410 So we have instance attributes and class attributes. 10 00:00:34,410 --> 00:00:39,630 So attributes can be either variables or methods, right? 11 00:00:39,660 --> 00:00:45,120 Now, in this video you will learn about properties, actually instance properties. 12 00:00:45,120 --> 00:00:51,510 So a property is a method which behaves like a variable. 13 00:00:52,450 --> 00:00:53,620 You'll see how. 14 00:00:53,800 --> 00:00:56,980 Let's go down to the reservation ticket class. 15 00:00:57,580 --> 00:01:03,220 We have two instance methods here currently in it and generate. 16 00:01:03,430 --> 00:01:09,430 And we will add another method which is going to be a property. 17 00:01:09,430 --> 00:01:13,630 So a special instance method called a property. 18 00:01:14,590 --> 00:01:23,950 So let's say that maybe the customer, they enter their name in lowercase letters and maybe they enter 19 00:01:23,950 --> 00:01:27,850 some unnecessary spaces when they type in their name. 20 00:01:28,220 --> 00:01:36,610 And so we want to clean that out, to remove the spaces and capitalize the first and the last name of 21 00:01:36,610 --> 00:01:37,600 the customer. 22 00:01:39,160 --> 00:01:44,430 A good way to do that would be inside a property and I'll explain you why. 23 00:01:44,440 --> 00:01:47,290 So let's create a. 24 00:01:47,880 --> 00:01:51,240 A method is called the customer name. 25 00:01:51,720 --> 00:01:56,640 You see, this is not a verb because this is a property. 26 00:01:57,240 --> 00:02:00,950 It makes more sense to be more like a variable name. 27 00:02:00,960 --> 00:02:04,050 I'll explain why when you call that property. 28 00:02:05,510 --> 00:02:09,770 And then you see a local variable. 29 00:02:09,770 --> 00:02:14,120 So this is just a variable which has meaning inside this particular method. 30 00:02:14,150 --> 00:02:19,430 This will be equal to self, that customer name that strip. 31 00:02:19,610 --> 00:02:23,210 So the strip method removes any spaces. 32 00:02:23,210 --> 00:02:31,400 So let's say that the customer name is John Smith with some space at the end. 33 00:02:33,380 --> 00:02:37,520 What we're doing here is customer name that strip and that will return. 34 00:02:37,520 --> 00:02:39,500 John Smith without the space. 35 00:02:42,460 --> 00:02:43,090 Right. 36 00:02:43,200 --> 00:02:45,790 And then again, we say name is equal to name. 37 00:02:45,820 --> 00:02:47,920 Dot title. 38 00:02:49,740 --> 00:02:53,520 So name will be John Smith without space and. 39 00:02:54,830 --> 00:03:05,210 Basically the second line we're doing this, so we get John Smith cleaned out with Capsulated in J and 40 00:03:05,210 --> 00:03:08,330 S, and then we return name. 41 00:03:09,250 --> 00:03:19,600 Now this looks just like a normal instance method to make this an actual property you use property decorator. 42 00:03:21,280 --> 00:03:22,620 I know you're still confused. 43 00:03:22,630 --> 00:03:24,130 What's the point here? 44 00:03:24,160 --> 00:03:25,200 Well, you'll see. 45 00:03:25,210 --> 00:03:26,570 What's the point there? 46 00:03:26,590 --> 00:03:34,620 So let's create a ticket is equal to reservation ticket. 47 00:03:34,630 --> 00:03:38,080 That's the name of the class which has this property. 48 00:03:38,530 --> 00:03:38,930 Right. 49 00:03:38,980 --> 00:03:40,150 Reservation ticket. 50 00:03:40,180 --> 00:03:43,060 It needs a customer name and hotel object. 51 00:03:44,800 --> 00:03:45,640 Customer name. 52 00:03:45,640 --> 00:03:52,000 Let's say the customer entered the name John Smith with the space and with lowercase letters. 53 00:03:53,860 --> 00:03:55,540 And hotel. 54 00:03:57,210 --> 00:03:58,230 Object. 55 00:04:01,020 --> 00:04:04,080 Is equal to a hotel instance. 56 00:04:04,080 --> 00:04:05,610 Hotel one, for example. 57 00:04:08,170 --> 00:04:14,140 Now with ticket dot the customer name. 58 00:04:15,730 --> 00:04:21,579 You can access the returned value of the customer name. 59 00:04:22,210 --> 00:04:23,650 Let's print this out. 60 00:04:23,680 --> 00:04:28,150 Print that and see what we get as output. 61 00:04:28,930 --> 00:04:32,410 So we get John Smith with Capital J and Capital SE. 62 00:04:32,440 --> 00:04:37,030 Now that means we can use the customer name. 63 00:04:40,500 --> 00:04:49,380 Insights here as well to generate the tickets or self the customer name, right. 64 00:04:51,650 --> 00:04:55,070 And so the benefit of this is that you don't need to call this. 65 00:04:55,070 --> 00:04:58,750 That's what makes this a property right. 66 00:04:58,910 --> 00:05:00,820 It behaves like a variable. 67 00:05:00,830 --> 00:05:09,740 It's defined as a method, but this decorator makes it behave like a variable. 68 00:05:10,790 --> 00:05:13,670 So let's call the generate method. 69 00:05:15,270 --> 00:05:19,410 Tickets generate generate doesn't take any. 70 00:05:20,290 --> 00:05:22,120 Arguments other than self. 71 00:05:22,210 --> 00:05:29,920 So we should see the output with John Smith printed out on the ticket. 72 00:05:32,500 --> 00:05:35,190 And so that's about properties. 73 00:05:35,200 --> 00:05:38,080 So you should use a property. 74 00:05:38,880 --> 00:05:49,170 When you think that the value this method returns looks more like an instance variable, but the value 75 00:05:49,170 --> 00:05:50,790 needs some processing. 76 00:05:50,790 --> 00:05:56,400 So you could also place these lines in the init function. 77 00:05:56,400 --> 00:06:04,860 So to modify the customer name by stripping it out and applying a title method, but that would be too 78 00:06:04,860 --> 00:06:08,040 much for the init function for the init method. 79 00:06:08,040 --> 00:06:15,090 So it makes more sense to create a property and then you can just access the customer name. 80 00:06:16,400 --> 00:06:20,420 As if it was a normal instance variable. 81 00:06:20,420 --> 00:06:29,580 So the benefit is that you keep this code enclosed inside a method, so that keeps things more organized. 82 00:06:29,600 --> 00:06:31,430 And yeah, that's about properties. 83 00:06:31,430 --> 00:06:34,820 And we have some more videos, so I'll see you in the next ones.