What is string.sub and how do you use it?

string.sub, sub means substring or part-of-a-string. It's basically taking a string and cutting off a piece of it. e.g.

print("Hello") --Hello

print("Hello", 2) --Ello

In string.sub it looks like something like this: string.sub("String", 2,4). string.sub is you know, string.sub. In the parentheses you have your string. "Hi", "Text", "string". Next you have a number. If it's just one number, that means anything before this number will be cut off. string. string.sub("String", 2) == "tring" --t is the 2nd number, 1 is before it so it gets cut off. If there is 2 numbers(you can only have 1 to 2 numbers) then it will cut off anything before the 1st number and anything past the 2nd number. string.sub("String", 2,4) == "tri" --ng and S get cut off. If you're wondering how do we know what numbers to use, lets say we have this weird string that has a message. "afakwshellosadffgafsadsadfge" we want it to say "hello". string.sub("afakwshellosadffgafsadsadfge", 6,11) --the 6th character in the string is "s". Everything before it(afakw) also get's deleted from the string. Now the 11th character is "s" again coincidentally. "s" and everything AFTER s is deleted(adffgafsadsadfge).

Hope it helps! If you're still having trouble understanding, please tell me!

Examples of string.sub in scripts:

1. Admin Scripts
2. Chat service

1. Admin

admin = {"LordDragonZord"}

game.Players.PlayerAdded:connect(function(player)
--	player.CharacterAdded:connect(function(char) --This isn't really necessary.
		for _,name in pairs(admin) do
			if player.Name == admin then
				player.Chatted:connect(function(msg)
					if string.sub(msg, 1, 5) == "Kill/" and game.Players:FindFirstChild(string.sub(msg, 6)) then
						game.Players:FindFirstChild(string.sub(msg, 6)).Character.Humanoid.Health = 0
					end
				end)
			end
		end
--	end)
end)

1. Chat

local default_color = "Blue"

game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(msg)
        if string.sub(msg, 1,2) == "R/" then
            game:GetService("Chat"):Chat(player.Character.Head,string.sub(msg,3),"Red")
        elseif string.sub(msg, 1,2) == "B/" then
            game:GetService("Chat"):Chat(player.Character.Head,string.sub(msg,3),"Blue")
        elseif string.sub(msg, 1,2) == "G/" then
            game:GetService("Chat"):Chat(player.Character.Head,string.sub(msg,3),"Green")
        else
            game:GetService("Chat"):Chat(player.Character.Head,msg,default_color)
        end
    end)
end)