Lua Tutorial

--[[

Hello! JumpYScriptsz here, I will try to explain the basics of how to learn scripting in (ROBLOX) Lua. Enjoy!

=====================================
----------\\ >> INDEX << //----------
=====================================

========== >> BEGINNER << ==========

1       Printing            = Line 31
2.1     Single Variables    = Line 49
2.2     Multiple Variables  = Line 60
3       Operations          = Line 159

======== >> INTERMEDIATE << ========

3.1     Further Operations  = Line 173
4       tables + functions  = Line 68
5       iterations (loops)  = Line 185
6       conditions          = Line 209

======= >> MISCELLANIOUS << ========

7       Value Types         = Line 150
8       The End Read        = Line 263

]]


--------------------------------------   { PRINTING }   --------------------------------------

print("hello world") -- outputs --> hello world
-- You can print multiple lines with [[]]
print([[
hello
world
]])

-- you can also print variables
-- A variable is a name that can hold a value
-- there are 2 types of variables: local and global

local i = 1 --> local (cannot be called outside a scope)
a = 1       --> global (can be used throuhout the script)

print(a)    --> 1

------------------------------------ { SINGLE VARIABLES } ------------------------------------

-- there are 4 values you can assign to a variable: nil, bool, numbers and strings

a = 1       --> number
b = "Nice"  --> string (anything inside quotes)
c = nil     --> no value, nothing
d = true    --> boolean (can be either true or false)

print(a,b,c,d) --> you can print multiple variables in one line --> 1 Nice nil true

------------------------------------ { MULTIPLE VARIABLES } ------------------------------------

local a,b,c,d = "hi",true,-1,nil    --> you can assign multiple values to multiple variables on one line

print(a,b,"some text: "..c,d)       --> hi true some text: -1 nil

-- , = spaces .. = concat (join together) e.g. "hi".."there" = "hithere"

------------------------------------ { TABLES AND FUNCTIONS } ------------------------------------

t = {} -- empty table

my_table = {somestring="test", 1, true, thingy=false, "BeepBoop"} -- you can assign any value/s or variables to a table

-- to add an object to a table we use table.incert(TABLE_NAME, VALUE)

table.insert(t,"wassup!") -- incerts the values into my_table

-- to referance (locate) an object inside a table you put: table name, dot, and the variable name

print(my_table.thingy)  --> false

-- alternatively you can referance the object position in the table by using []

print(my_table[3])      --> BeepBoop

-- [3] represents the third value in the list.
-- A position with a higher value than the number of items in a table returns nil (as it does not exist)

-- to loop through all values inside a table we use ipairs where:

--> the first variable is the number
--> the second variable is the name

for i,v in ipairs(my_table) do -- cycles through values in the table "my_table" with the variables i (number) and v (name)

    print("Value is",v,"in place",i) -- outputs the following:

    --> Value is 1 in place 1
    --> Value is true in place 2
    --> Value is BeepBoop in place 3
    --> Value is wassup! in place 4
end

-- functions are things we call later on in a script
-- we could use local functions (private) or global functions
-- functions can pass params (values) into it
-- example: adding function

i = 3
e = 6

function add()
    local sum = i + e -- sum can only be called within this function
    print(sum)
end

-- print(sum) --> sum not defined

-- declaring variables in functions we use local
-- this is to make sure a variable with the same name in another place does not override it
-- to call the function we say the name of it followed by 2 brackets (params)

add() --> 9

-- to pass params (values) to our function we use name values
-- these value names can be anything

function multiply(a,b) -- a and b for example
    local sum = a*b -- * = times
    print(sum)
end

-- this function takes 2 params, multiply them and output the answer


multiply(4,3) --> 12


-- we seperate our input values with commas

-- if there is a list of variables you want to save, we use ... (a table which can hold an inf amount of data)

function my_func(thing, ...)
    print("I am going to see a",thing,"with", ...) --> I am going to see a movie with Charly Zak Fred James
end

my_func("movie","Charly","Zak","Fred","James")


------------------------------------ { CHECK VALUE TYPE } -------------------------------------

-- you can use type() to check what type the value is

print(type("Hello world"))  --> string
print(type(10.4*3))         --> number
print(type(true))           --> boolean
print(type(nil))            --> nil

---------------------------------------- { OPERATIONS } ---------------------------------------

-- there are 4 main types of operations you can use: + - * /

add = 1+5  -- 1 plus 5
sub = 9-4  -- 9 minus 4
div = 12/4 -- 12 divided by 4
pow = 10*2 -- 10 times 2

print(add) --> 6
print(sub) --> 5
print(div) --> 3
print(pow) --> 20

------------------------------------ { FURTHER OPERATIONS } -----------------------------------

-- there is also a built in math function which you can do other operations

print(math.random(1,10))    --> random number between 1 and 10
print(math.huge)            --> inf
print(math.round(14.3))     --> 14 (round numbers up or down)

a = (10/2)+4

print(math.sqrt(a))         --> 3 (you can even pass operations as variable form)

---------------------------------------- { ITERATIONS } ---------------------------------------

-- iterations (loops) allows us to repeat
-- try avoid while true do with no wait() as it lags

while wait(.1) do   --> this will run forever every 0.1 seconds
    break           --> allows us to stop the forever loop
end

-- we can also set conditions to our loops so they can stop

for i = 0,5 do  --> counts from i = 0 to i = 5 then stops
    print(i)    --> 0 1 2 3 4 5
end

-- repeat untils are useful to
-- use 2 equal signs to check if a condition matches another condition / value

e=0

repeat e += 1   --  you could use e=e+1 but this is shorter (add one, save value, add one to that saved value and so on)
    print(e)    --> 1 2 3 4 5 6 7 8 9 10 11 12
until e == 12

--------------------------------------- { CONDITIONS } -----------------------------------------

-- conditions can be represented as many things. Some being: true, false, ==, ~= (not equal to), or, and

value = true

if false then -- false is a constant along with true and nil (does not change)
    print("this will not print")
end

if value == true then
    print("value is true!")
end

-- we can shorten this down

if value then
    print("value is true!")
end

-- alternatively we can use "not"

if not value then -- if not true then...
    print("value is false")
end

-- we can check our value by merging both of these together as one statement

t = false

if value then
    print("value is true!")
else
    print("value is false!")
end

-- we can also embed mutliple if statements into one

test = "hello person" -- change this value type to whatever to test it!

if type(test) == "boolean" then -- check if the value is a boolean
    if test then
        print("test is true!")
        -- alternatively can be written as...
        print("test is",test.."!")
    else
        print("test is false!")
    end
elseif type(test) == "string" then   --> we use elseif in one if statement to check for supposed multiple outcomes
    print("value test is a string!") --> this will be printed
else -- if no conditions are met
    print("Value test is not a boolean or a string! It is a",type(test).."!!!")
end

-- I hope you have learned some things about lua and how to script! - JS