a purely "academic" topic - global variables should never be used.
Everything in Ruby is an object and classes are the blueprints from which objects are created.
In Ruby, a function is a set of statements that performs a specific task and help to organize code and make it reusable. They allow you to break down a complex problem into smaller, more manageable parts.
Ruby blocks are a powerful feature of the language. They allow you to write concise and expressive code, and are used extensively in the standard library. There are many advanced techniques that you can use to get the most out of them.
In Ruby, a block is a piece of code that can be executed. It is similar to a function or a method, but it is not an object.
A Ruby hash is an unordered, dictionary-like collection of pairs of keys and values. They can be of any type and you can intermix different types inside a particular hash, as long as all the keys are unique.
Ruby arrays are ordered collections of objects; they can be of any type and you can intermix different types inside a particular array.
Comments are an essential part of the code and are used to explain the purpose of the code and make it more understandable for other developers.
Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.