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hey welcome to draft Academy my name is Mike in this tutorial I want to talk to you guys about the initialized method in Ruby classes so in the last tutorial we looked at creating Ruby classes and then creating objects of those classes in this tutorial I'm gonna show you a way that we can actually make creating these objects a little bit easier so you'll notice down here when I created my two book objects I said book 1 is equal to book new and then I had to manually set the books title of the books author in the books pages so just to create one book I had to type out four full lines of code right down here I'd do the same thing so when I created the second book had to type out four full lines of code and this is kind of a problem because if I wanted to create for example like you know 10 or 20 different books it's gonna take up seriously a lot of space inside of my Ruby files also just having to go through and manually say like book 1 title is equal to Harry Potter book 1 author like that gets really tedious after a while there's actually a way that we can give our objects all this information right up front when we create them instead of having to do it manually like this and that's by using something called an initialize method an initialize method is actually a method that's gonna get called whenever we create an object so remember up here we have this class and this class is basically just a template it's a blueprint for what a book is in our program when I create an object it stops being a template it stops being a blueprint and it becomes an actual book so this book one object down here is representing the Harry Potter book you know with the author of JK Rowling four hundred pages this is like a physical book that we use that template up there to create so when we end up creating a book we can actually give it some default information and I'm gonna show you guys how to do that so up here in our class I want to create a method and it's gonna be called initialize so I'm just gonna say def and it's initialized just like that and I'm actually going to create this just like I would a normal method so I'm gonna say n down here inside of these parentheses I can actually pass some information but before I do that I want to show you guys what's gonna happen so for example I could put a print statement here actually let's do a put statement and it's gonna say creating book now when I run my program you'll see that over here it actually types out creating book twice essentially what's happening when I say book dot new this initialize method up here is getting called so every time I use this new method down here and I call it this initialize method is actually getting called so if I was to pass a parameter into here so let's have this initialize method take a parameter like we'll have it taken name I could come over here and I could basically print out like hello name so I could pass a name into here I could say like Mike and then down here I could say another name like Bill or whatever and when I run my program you'll see it's printing out hello Mike and hello bill so this is essentially just a method that we can call just like any other method in any of our programs but this method special because it gets called when we create an object so what we can do is we can actually pass this initialize method some information and we can use that information to give our object specific information so essentially what I can do over here is I could say initialize is going to accept three parameters so when we call this new method down here we're gonna have to pass it three things the first thing we're gonna have to pass it is the title of the book that we want to create the second thing we're gonna have to pass it is the author of the book we want to create and the third thing is going to be the number of pages for the book that we want to create so now whenever I want to create a book I have to give it a title and author and a number of pages once I'm inside this initialize method I can do something special so I can actually take the values that the user passed in so I can take the title the author and the pages and I can assign them to the attributes of the object so I can assign them to the title of the object the title of the author and the title of the pages I can basically do what I did down here so I can basically say like book one title is equal to whatever the title they passed in was and this is gonna save us tons of time we're writing our programs and the way that I can do that as I can I can just say app and I can say title is equal to title so let me walk you guys through this line of code when I say app title this is referring to the title attribute in our object it's referring to the title attribute that's we defined up here is referring to that title up there right this is saying the title of the object that we're creating is going to be equal to the title that the user passed in remember this title this is just a parameter that got passed into this new method down here this is just a parameter just like I passed in the name it's the same thing we're passing it a parameter and I could even name this something else I can name this like you know I couldn't I can name it you know whatever I wanted and but I'm just calling it title because that's what it is it's the title so I'm setting the title of the object equal to the title that got passed in I can do that for all of these so I can say the author of the object is going to be equal to the author that got passed in and the number of pages is going to be equal to the number of pages that got passed in and so essentially what I can do now is when I create my new book instead of having to say like book 1 titled book 1 that author I can just take all this information and put it up here so I can pass it into this initialize method so I can just say Harry Potter and this is gonna be JK Rowling and then the number of pages is just gonna be 400 so I can actually get rid of all of this code over here because I don't need this anymore and I can do the same thing for this other book down here so we'll pass in Lord of the Rings Tolkien and 500 pages and I can actually just get rid of all of this stuff so now instead of having all that other stuff like where I had to like manually set each of those attributes I can reduce the lines of code I have right down to two and this is gonna do exactly the same thing as we were doing before so I could come down here and I could you know print out like book to title and it's still going to be able to print it out to see it's printing out Lord of the Rings I could print out book 1 dot Arthur and it's gonna be able to print that out so I'm doing exactly what I was doing before except now I'm making it a lot easier on myself by using this initialize method and again whenever we say like book dot new this means we're calling this initialize method we're passing it some parameters and I'm setting the attributes of the current object equal to the attribute that we pass in when we create that object so that's how we can use that initialize method to make our lives way easier and you're always gonna want to use an initialize method for the most part just because it makes everything so convenient hey thanks for watching if you enjoyed the video please leave a like and subscribe to drop acad to be the first to know when we release new content also we're always looking to improve so if you have any constructive criticism or questions or anything leave a comment below finally if you're enjoying chopper Academy and you want to help us grow head over to draft Kadim e-comm forward slash contribute and invest in our future