Chapter 2: Variables & Data Types

Types

GLang gives you the option to store data in the form of a type. This data can be accessed via a variable (a little object stored in your computer's memory)

There are three primary types in GLang, number, string, and list. The number type is hinted by the name, a number.

10

The string type may be a little confusing, but its actually a collection of characters (a.k.a. a string of characters)

We can use this to store text of any length - from your favorite quote to an 8 page essay, the string type can hold it.

"This is a string of text. We can add emojis 😼, special characters !#@$^#, and even other languages 你好."

Lastly there's the list type, an infinitely grow-able "storage container" of items. The list type can hold every other type, multiples of it, and even itself.

[1, 2, 3, 4, 5]

We'll talk a bit more specially on this type later on, but for now, think of it as a bag of groceries, it can hold a lot of things!

Variables

The most important part of programming is storing data for later. Programmers often do this by creating a variable; a named object stored in memory.

obj x = 10;

Here, we use the word obj to tell GLang we are creating a variable (object). We then give it the name, x, and assign the value to 10 (our awesome number type!) This name, x is stored in memory for use anywhere in the program.

To change a variable’s value, just assign a new value to it (without obj)

x = 20;

The cool thing about variables are their ability to have names other than x. Variable names can:

• contain letters, numbers, and underscores
• not contain spaces or special symbols (like ! or $)

obj my_favorite_number = 69;
obj _____a_variable_with_a_lot_of_underscores_____ = "A lot of underscores";
obj MY_3_FAVORITE_FOODS = ["Cake", "Pizza", "Burgers"];

Constants

Additionally, there are constants. Much similar to variables, they can also store data, however, they store data in a non-modifyable form. This means we can never change a constant or it's data once it is created.

stay X = 10;

X = 20; # this line causes an error

It is preferred to keep a constant's name fully uppercase, as they are best used for values you use everywhere in your program.

stay MAX_STORAGE_AMOUNT = 240; # this way, 'MAX_STORAGE_AMOUNT' stands out from 'max_storage_amount'