Let's start off with a simple question: what is a variable? Depending on your point of view, there are a few different ways of answering that question, as follows:
- Conceptually, a variable is the most basic unit of programming, such as an atom. Everything starts with variables, and programs can't exist without them.
- Technically, a variable is a tiny section of your computer's memory that holds an assigned value. Every variable keeps track of where its information is stored (this is called a memory address), its value, and its type (for instance, numbers, words, or lists).
- Practically, a variable is a container. You can create new ones at will, fill them with stuff, move them around, and reference them as needed. They can even be empty and still be useful:
A useful real-life example of a variable is a mailbox...