Some confusion with string.sub()

You can write your topic however you want, but you need to answer these questions:

  1. What do you want to achieve? So I am working on an admin commands project that has multiple commands an admin can use. One of the commands I am having problems with is !gshutdown, which is global shutdown that shuts down all servers of the game. I want the admin to also be able to provide a reason for why the shutdown happened, and if there is no reason, it would return “No reason provided.”.

  2. What is the issue? When the admin doesn’t enter a reason, the reason variable will be just be “n”. If the admin inputs a space, the reason variable will just be a space. I’m just wondering if there’s any alternative method I should use. I will not use string.split() though.

  3. What solutions have you tried so far? Yeah, so I tried using string.split() the very first time and obviously, it separated all the words. Then I began trying to use string.sub() but now I’m having this problem.

For those who thing I should do this:

local Reason = msg:sub(string.len("!gshutdown")) or "No reason provided."

No, it does not work.

-- rest of the code....
elseif string.match(msg:lower(), "!gshutdown") and table.find(Admins, plr.UserId) then
			if EnabledCommands.GlobalShutdown then 
				local Reason = msg:sub(string.len("!gshutdown"))
				GlobalShutdown.Main(Reason, BlacklistedUsers.GlobalShutdown, plr)
-- rest of the code....

I’m not completely sure but I think string.sub is including the n at the end of !gshutdown, So you would have to do a +1 to the result of string.len.

Yes, I tried that as well, but then it would still return a space. And I think the same thing, that is indeed the case.

You’d better use the string.match function.
Here is an example of implementation:

local cmd = "!gshutdown         Game Test"
local pattern = "!gshutdown%s+(.+)"    -- matches "!gshutdown" and any number of spaces (one or more). Also, captures the reason argument.
local Reason = string.match(cmd, pattern)

if Reason == nil or string.match(Reason, "^%s+$") then	-- if the reason is all spaces or nil (not provided)
	Reason = "No reason provided."

print(Reason)  -- outputs "Game Test"
1 Like

Alright, I’ll try it tomorrow.

Thanks a lot! It works very well. Did you do this all by yourself or look at docs? String patters seem very useful and I’d like to learn them.

This actually was a simple pattern, there are complicated ones other than this.

Let’s say, I have to look at the documentation if I’m not sure about the pattern I’m writing, along with trying it on a web-based compiler to check if it works.

You will surely look on the Roblox documentationString Patterns or Lua org documentation for patterns.

So here I assume you used a space as your separator for the string.split(), if you, however, used the command (!gshutdown ) followed by a space, then the second index would be the reason!

Just adding information here, I am aware it has been solved.

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