The Ruby Standard Library

[MUSIC] 0:00 While Ruby Core contains modules and classes, 0:04 the Ruby Standard library contains larger pieces of functionality and 0:07 must be specifically imported into your programs. 0:12 Some examples of standard library are utility classes for working with dates and 0:16 times, serialization, network access, and more. 0:21 We could do a whole course on every piece of the standard library. 0:26 However, we're just going to look at some of the different pieces of functionality 0:30 available today. 0:34 What we see here is the Ruby Standard Library Documentation. 0:36 Now, the main panel says just a little bit about how the documentation was generated. 0:40 And gives thanks to the people who helped make it happen. 0:45 On the left side of the main documentation, 0:48 you'll find the table of contents. 0:51 This lists every available package in the standard library and is sorted by letter. 0:53 If we click into a package, we'll get the documentation format that we're used to 0:59 for other classes and modules. 1:04 Most documentation for items in the standard library will be split up 1:08 among different classes and modules. 1:12 This naming scheme is common in Ruby and encourages separation of concerns when 1:14 coding projects larger than just a few methods or files. 1:19 Right now, I've loaded up the documentation for CSV, which stands for 1:23 comma separated values. 1:28 This is a common format which seems easy to implement programmatically, but 1:30 is actually quite involved, which is why there's a library for it. 1:35 Now that we click into the standard library for 1:38 CSV, we'll see a bunch of different classes. 1:41 Most commonly, the documentation for 1:46 what we want will have the same name as the package. 1:48 In the CSV example, I'm gonna click on the top level CSV class again. 1:52 When I do that, we get a description of what the package does, 1:58 followed by some code examples of how it can work. 2:02 We can generally use these code examples 2:05 as a guide to accomplish what we want to in our programs. 2:08 On the left side, we have the usual method list that the class supports. 2:11 In larger packages, like we find in the standard library, we'll also see a name 2:16 space section which will show any other sub classes that this library has. 2:21 Finally, if we scroll down we can see any modules that are included with this class, 2:26 and also included in the library. 2:32 Some packages like this one for CSV may also have notes, 2:34 gotchas, warnings or other things to keep in mind when coding. 2:37 This one contains notes on how different character and codings are handled. 2:42 And also a note that we may find bugs in the code, 2:47 as well as where to report the issue. 2:50 When we get a little further into the documentation, we'll also see a list of 2:53 constants in the class before the rest of the methods are listed. 2:57 One thing that's interesting to note about packages in the standard library, 3:01 is that they have to be explicitly required. 3:04 For example, if I open up irb and try to access the CSV class, 3:08 I'll get an error saying that there's an uninitialized constant. 3:13 In order to use it, I'll have to explicitly require CSV. 3:17 Once I do that, I'll have access to the CSV class. 3:21 If I click back into the rest of the standard library documentation, 3:26 we can see that there's a wealth of functionality available to us. 3:30 The Benchmark module for 3:34 example, will allow us to measure the time it takes our code to run. 3:36 This can help us if we're trying to optimize different pieces of code, and 3:41 get an idea of where the bottlenecks might be in our programs. 3:45 The CGI library is larger library for working with low level web requests and 3:52 has several sub classes inside of it. 3:58 If we go back even further, the FileUtils module 4:02 gives us a platform agnostic way to work with files and directories. 4:06 We can do things like change and list directories, copy, move files, and more. 4:12 As we keep scrolling through the documentation for 4:19 the standard library, we'll see different sections. 4:21 For example, Net/HTTP, 4:25 the Net HTTP module can be used to consume APIs, and 4:29 also fetch and work with webpages programatically. 4:33 It's a good idea to read over the classes and libraries in the standard library. 4:37 By being familiar with the standard library, 4:41 you'll have a leg up on programming, and 4:43 not be tempted to re-implement these pieces of functionality on your own. 4:45 Some classes to be familiar with are forwardable, 4:49 observer, prettyprint, optparse, and more. 4:54 Using the documentation link below, 5:01 try reading through some of the standard library documentation now, and 5:03 practice with some of these classes on your own using workspaces. 5:07