Man With Code 👨‍💻

Covered in this Episode:

• What is YAML
• Why should you use YAML?
• Storing Data

Transcript: Hello Everybody and welcome to Programming With Ruby Episode 14, YAML. I'm Tyler and this video is brought to you by manwithcode.com. I will start off this episode telling you what YAML is and why you should be using it. I will then be showing you how you can store objects and various assorted other kinds of data using YAML. Without further delay, lets get started! What is YAML? YAML stands for YAML Ain't Markup Language. In the most basic sense it is a way of storing data for later use. Why should you use YAML? Lets say you are writing a game, you could save your players progress to a YAML file. Or if your writing an application with many preference settings, you might save the user's preferences to a YAML file. Using YAML instead of creating your own text-based format creates more portability, because other applications can immediately use your YAML file instead of having to write their own custom file loader. YAML also makes editing files by hand very easy to do if you have to. Enough of all the theoretical talk, lets write some code! Storing Data Lets say we are writing a text editor and there are a few preferences the user can change. We want the user to be able to set their preferences and have them saved, so the next time they start up our text editor the preferences are set the same as they were at last use. We decide to use YAML to store our users preferences. Lets say for example that the preferences are stored in a hash: [ruby] @preferences = {"word-wrapping" => true, "font-size" => 20, "font" => "Arial"} [/ruby] To save that using YAML we have to use: [ruby] require 'yaml' [/ruby] Open a file for writing (YAML files end in .yml or .yaml): [ruby] output = File.new('prefs.yml', 'w') [/ruby] Use the YAML.dump method to get the text that will be outputted: [ruby] output.puts YAML.dump(@preferences) output.close [/ruby] Full source: [ruby] require 'yaml' @preferences = {"word-wrapping" => true, "font-size" => 20, "font" => "Arial"} output = File.new('prefs.yml', 'w') output.puts YAML.dump(@preferences) output.close [/ruby] And that is how easy it is to store data! We read back a file in a similar way, using the YAML.load method: [ruby] require 'yaml' output = File.new('prefs.yml', 'r') @preferences = YAML.load(output.read) output.close [/ruby] Don't think you're limited to simple data like hashes and arrays, you can store objects too! It has been my experience that it is usually best to store data in hashes, because they automatically have a label, unlike an array. You can do whatever you want to, but that is my recommendation. Now comes the sad time when we have to close the episode. Please don't forget to donate, a few dollars can go a long way. If you have any questions, comments or suggestions, please do not hesitate to leave a comment below or email me at [email protected] Thank for watching! Bye!