Creating A Class Part 3

Quick reference

• 00:04 Okay, so we've got our class, we've got our initialization method,
• 00:07 our __init__ method.
• 00:08 And we're passing in these parameters,
• 00:11 we're turning them into instance variables.
• 00:13 Instance variable just means you can use it inside of the class,
• 00:16 in all of the different methods that you create.
• 00:19 In our case, we've only got one method here, but that doesn't really matter.
• 00:22 So right now, we can print out all of these things, and that's kind of fun, but
• 00:26 it's not all that useful.
• 00:27 Let's create another method and give this class a little bit more functionality.
• 00:31 So super easy to do.
• 00:33 And be sure your definition statements line up, because indentation is important,
• 00:37 obviously, in Python, and especially in these classes.
• 00:40 So to create a new method, let's go def, and then let's call this report.
• 00:45 We want to create a little report of our employee, right,
• 00:48 because we've got all this information, let's create a report.
• 00:51 So we create a method, which is basically just a function, and like any function,
• 00:54 you gotta pass in those parameters.
• 00:56 And remember, when we built this one, I said all of our methods are going to start
• 01:00 with self, and that's true here too, so self.
• 01:02 And if we wanted to pass in other stuff, we could do it here.
• 01:05 But we don't really want to pass in anything in this method,
• 01:08 we just want to get information out of it.
• 01:09 So then we got our colon, now what do we want to do?
• 01:12 Well, let's take all this information and sort of format it into a little report.
• 01:16 And we can do that a bunch of different ways.
• 01:17 I'm just going to do a real quick print statement, just to sort of show this.
• 01:21 And so let's go, self.first_name +, and then I'm going to put a little space.
• 01:27 And this is how you add little spaces to things, just add this +.
• 01:30 I think we've probably looked at this before.
• 01:32 And then self.last_name, and then another little space,
• 01:38 and then let's go, self.email.
• 01:41 You notice we have to address these as self, you can't just put the name itself,
• 01:45 because up here, they're self., self., self.
• 01:48 So whenever you use them throughout your class, you have to do self., as well.
• 01:52 So then self.pay, now, you see right away, we get this X here, all right?
• 01:59 There, it disappeared, but nonetheless, we're still going to get an error.
• 02:02 And in fact, if we come down here, to use this to access the report method,
• 02:07 we just type in report.
• 02:08 And then like any method that we want to call, any function we want to call,
• 02:12 we have to pass in the parameters.
• 02:13 Of course, in this case, we don't have any, but
• 02:15 we still have to put these little parentheses.
• 02:16 Nonetheless, if we run this,
• 02:18 we're still going to get an error because, see this self.pay?
• 02:22 These are all strings, but pay is an integer.
• 02:24 And so we're trying to add an integer to a string, and you can't do that.
• 02:28 You can add strings to strings and do it like that,
• 02:31 you can't do it with an integer.
• 02:33 But we want to access this, so
• 02:35 we already learned in the past how to convert an integer into a string.
• 02:38 We just call the str function, and wrap it all in there.
• 02:43 So now that should work.
• 02:44 But from now on, this is a string in this method, so keep that in mind.
• 02:49 So now if we run this, we get John Elder, email address.
• 02:53 We forgot a space, put a space in there, there we go, John Elder, and we get this None.
• 03:00 We could play around with this, and turn it into a return if we like,
• 03:05 get rid of that.
• 03:06 So just like that, we have this nice little John Elder, email, and
• 03:10 hey, and that's the little report that we can do.
• 03:12 And this will work irrespective of what information we put in here.
• 03:17 So we can create employee number 2, and set that equal to Employee of Tim,
• 03:26 Smith, Tim@tim.com.
• 03:30 And poor Tim only makes $40,000.
• 03:34 So now if we come down here and
• 03:36 just change this from employee_1 to employee_2, boom.
• 03:40 Tim Smith, Tim@tim.com, $40,000.
• 03:42 So this is the essence of creating a blueprint.
• 03:45 It doesn't matter what inputs you put into it,
• 03:49 you're going to get out whatever the blueprint has done.
• 03:52 So we put in Tim, we get out Tim, we put in John, we get out John, so very,
• 03:56 very cool.
• 03:57 And I hope that sort of shows you kind of the blueprint-iness
• 04:01 of what classes are and how they work.
• 04:03 And you see this .report, anytime you create a method inside your class,
• 04:07 you just call it just like this.
• 04:09 So if we created a method called fire, like we're going to fire an employee,
• 04:14 then we would come down here and def fire(self).
• 04:21 And then whatever we wanted that method to do, we would just print it out.
• 04:25 And then whenever we wanted to access that, we'd just call the fire method,
• 04:30 right?
• 04:30 Very cool, just let me get back to report, very awesome.
• 04:34 And in this case, we didn't create any other parameters.
• 04:36 But if we did, you would put them right here, separated by commas,
• 04:40 like you always do with other functions, and it's just that easy.
• 04:43 So that's classes, just awesome, right?
• 04:46 So in the next video, we're going to look at built-in class attributes.

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