Creating a Script

Coding is the process of creating instructions for computers to follow. Just like people use different languages, such as English and Spanish, so do programs. Roblox uses the coding language Lua.

This article will cover how to start coding in Roblox, introducing common concepts like scripts, data types, and variables. By the end, you'll be able to type out code that displays messages in Roblox Studio.

Coding with Scripts

In Roblox Studio, lines of Lua code are held in scripts. These scripts give the game sets of instructions on how to give players health points, create a rain of fireballs, or anything else imaginable.

Scripts are commonly created in ServerScriptService, a special folder made just for holding scripts.

In Explorer, hover over ServerScriptService to see the + button.
Click the + button and select Script. A new script will be created and the script editor will open.
Right-click Script and select Rename. Name the script PracticeScript. Naming scripts helps you and any teammates remember what each script does.

Hello World

New scripts include a print function at the top of the script editor. Print functions display text on the screen. It's one of the first functions many people learn, and you'll use it often. This code will make "Hello world!" appear on the screen.

Default code
print("Hello world!")

To find the script next time you open up Roblox Studio, click on the name of the script above the game editor, or double-click the script's name in Explorer.

Testing Output

You can see the result of running the default code with the Output window. The Output window is typically at the bottom of Roblox Studio, but if you've never used it before, you may need to enable it.

You'll need the Output window throughout this course, so now is a good time to enable it if you haven't already.

Select the View menu tab.
Click Output.

The window will appear at the bottom of Roblox Studio.
To test the script, click Play. Hello world! will show up in the Output window.
Click Stop to end the playtest. You can now return to the Script tab.

Identifying Data Types

Coding languages classify different kinds of values into data types. For example, one data type is a number. Number data types are self-explanatory as they are made up of only numbers.

Another data type is a string. Strings can hold numbers, letters, and characters. Take another look at the default code in the new script; the words and quotations within the parenthesis is an example of a string data type.

Default code
print("Hello world!")

Strings like "Hello World" always sit inside quotation marks, "like this". More examples of strings are below. Notice how they hold a mix of letters and numbers.

"You just joined the game!"
"There are 50 players left"
"10"

Creating Variables

Variables are containers for information the program can use and change, like player names or points.

Declaring a variable is what coders call the process of creating a new variable. In Lua, to declare a new variable, type local, then type the name for the new variable. A variable that can hold a player name might look like: local playerName

When declaring new variables, some coding languages require that you also state what data type the variable can use. For example, a variable in Java would be String name = "Pavel". Lua only requires a name.

In Lua, variables can be global or local. You'll usually use local variables. Local variables can only be used within the script or chunk of code where they were created. Global variables can potentially be used by other scripts, but too many global variables can make your experience slow and unresponsive. It's better to stay in the habit of making variables local unless necessary.

Using Variables and Strings Together

Time to declare your own variables. These steps will use a string to store the name of your favorite animal.

Delete print("Hello world!"). It's best practice not to leave unnecessary code in your scripts.
Declare a new variable by first typing local, then naming the variable myAnimal.
```
Declares a new variable
local myAnimal
```

Variable names can't include spaces. Be careful not to include spaces or the code won't work as intended.

Naming Variables

Variables can be named anything, but good names will always describe their purpose. Generic names make your code difficult to read and update later. Coders will also use different capitalization styles to remind themselves how the variable is used within the script. A good default style is camelCase.

To write in camelCase:

Begin with a lowercase letter
Leave out spaces
Capitalize additional words

Good Variable Names

playerPoints
numberStorageArray

Bad Variables Names

myVariable - Doesn't describe the purpose of the variable
player name - The included space will cause issues

Assigning Values to Variables

New variables are empty. To assign it a value, or put something inside its container, use the = symbol. In this case, assign the variable the name of your favorite animal.

After the variable name, type =.

Equal assigns values
local myAnimal =

On the same line, type a string that contains your favorite animal. Remember the quotation marks.

Assigns "Porcupines" to myAnimal
local myAnimal = "Porcupines"

Using Print() For Your Own Messages

Print functions display text on the screen, as you saw earlier. It's one of the first functions many people learn since it's a simple way of giving the script a command. To see your variable, use the print() function.

On a new line, type print().

Adds empty print()
local myAnimal = "Porcupines"
print()

Type the name of your variable within the parenthesis.
```
Outputs "Porcupines"
local myAnimal = "Porcupines"
print(myAnimal)
```
If you see a red error in the output editor, it's like there's an error in the code. Each error has a unique way of describing itself. Try and use the information from the error to fix your code.
Test your code with the play button. You should see the name of your animal in the Output window.

Combining Strings

You can display any string in the Output using print(); you can even print multiple strings stored within variables or typed directly within the function. Concatenation is combining strings. To concatenate the string assigned to your variable and a second string, use two dots .. The following example concatenates two variables and two typed strings.

Uses variables and strings together
local firstAnimal = "porcupines"
local secondAnimal = "dolphins"

print("I like " .. firstAnimal .. " and " .. secondAnimal)

Play around with printing different combinations of strings.

Summary

New scripts can be created by clicking the + button next to the name of an object. ServerScriptService is a common place to create new scripts. New scripts include the default code print("Hello world!"). This code will display Hello world! in the Output window, where you can see the results of your code and if any errors have occurred.

"Hello world!"' is an example of a string data type. Strings can include any combination of characters that you might type on your keyboard. Concatenation is when multiple strings are combined.

Variables are containers that can be assigned to hold different data types, such as strings and numbers.