Ruby Core contains the classes and modules that come with Ruby and make Ruby work. 0:05 For example, Ruby Core contains many familiar classes that you've worked with 0:10 so far, things like Array, Hash, Fixnum, and more. 0:15 Let's take a look at some of what Ruby Core has to offer now using workspaces. 0:21 So here is the Ruby Core documentation. 0:26 Now, you'll find a link to this in the notes right below the video. 0:29 So, you can go ahead and look that up and follow along. 0:34 Now, when we look at the documentation, on the left side here, right on top, 0:37 the first thing that we have is a list of files. 0:41 This documentation format is relatively standard for Ruby Core, 0:45 standard library, and even some gems. 0:50 Here we see on the left side, 0:53 that is all of the different files that would be in this package. 0:54 And right now these are just documentation links. 0:58 Here is where documentation gets good. 1:03 On the left side, 1:06 we have all of the different classes that are part of Ruby Core. 1:07 Some of these are going to look very familiar, like Array. 1:12 I'm gonna go ahead and click on this here and we can see the Array documentation. 1:16 Once we are inside of the Array documentation, 1:22 we get a list of methods all the way down on the left side here. 1:26 This is going to be the different instance methods that are supported by Arrays. 1:30 On the right side of the documentation, there will be an introduction. 1:37 This isn't the same for every single class and module in Ruby Core however, 1:41 there could be some nice examples in this part of the documentation. 1:47 So we some examples of using an Array and what can be inside of an Array. 1:52 Sometimes the documentation will give you little hints about how to use a class or 1:57 module, and here is an example of that. 2:03 If we wanna create an Array with separate objects, 2:08 a block can be passed in to the Array instead. 2:11 Now, if I hit the Back button, you can see there are more classes and 2:16 modules that you might be familiar with. 2:20 For example, Strings as part of Ruby Core. 2:23 On the right side of the documentation 2:28 are all of the different methods that are found in Ruby Core. 2:31 These will have parenthesis on the ride side that shows you what class or 2:37 module they come from. 2:42 And, if we want to, we can filter these classes and methods. 2:45 For example, if we wanted to see what classes and 2:50 modules contained the word Object, we could do that. 2:53 The methods can be interesting, too. 2:57 If we want to filter the methods to see what's supported, for 2:59 example the to_s method which converts something to a String. 3:03 We can see all of these different classes and modules support the to_s method. 3:07 Also to_i, to convert something to an integer. 3:15 To_f for floating point. 3:19 To_a for Array and to_h for Hatch. 3:23 It's good to be familiar with the different classes and 3:30 modules that are part of Ruby Core. 3:33 Go ahead and 3:37 take a look at all of the different ones here on the left side of the screen. 3:38 Try looking around at the Ruby Core classes on your own now using Workspaces. 3:43