Subtracting letter from a string

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#1 
	for i,v in pairs(GUI.InventorySlotsBackground:GetChildren()) do -- loop through the inventory slots
		if v:IsA("ImageLabel") and v:FindFirstChildWhichIsA("TextLabel") then -- if v is an inventory slot, then
			local Amount = v:FindFirstChildWhichIsA("TextLabel") -- text label is equal to the amount of items the player has
			if tonumber(string.gsub(Amount.Text, "x", nil)) then
				print(tonumber(string.gsub(Amount.Text, "x"), nil))
			end
		end
	end
	task.wait()

I made a script which is meant to be removing the letter “x” from the TextLabel’s text, and printing it out. The text is equal to the amount of items a player has, but has an X at the end. For example, if the player has 30 wood, the text would say “30x”.

The 3rd argument has to be a replacement for the letter x, which I don’t want, so I put nil. This is giving an error: invalid argument #3 to 'gsub' (string/function/table expected, got nil)

#2 
string.gsub(Amount.Text, "x", nil)

this is the main piece of the script i’m having an issue with

#3

Replace the third parameter in the string.gsub function with "".

When you leave that parameter as nil, it thinks you haven’t defined a string to replace it with.

#4 
			print(Amount.Text)
			if tonumber(string.gsub(Amount.Text, "x", "")) then
				print(tonumber(string.gsub(Amount.Text, "x"), ""))
			end

image
Line 82 is print(Amount.Text). I want to check if the amount is less than 0

#5

gsub returns a string and a number
string is the new created string
number is amount of changes
all you need is this

print(Amount.Text)
local s = string.gsub(Amount.Text, "x", "")
if tonumber(s) < 0 then
    print(s)
end

the error tells you that you used an out of range baste tonumber(string, base)
gsub returns here 69 and 1 because we change one x to empty so what you did is this tonumber(“69”, 1)
which is invalid

#6

string.gsub returns two values, the first is the filtered string, and the second is the amount of replacements made. You are giving the tonumber() function 2 variables, not 1.

I would also recommend running the string.lower() function on Amount.Text to turn and uppercase X into a lowercase x to filter both types of xs on the string.gsub() function.

I also added the or 1 in the event that the string the player entered is not a number which would cause the script to error because nil < 0 is not possible.

local FilteredText = string.gsub(string.lower(Amount.Text), "x", "")

if (tonumber(FilteredText) or 1) < 0 then
    --// Your Code Here
end
#7

Use string.find or string.match, both return ‘nil’ if the search pattern isn’t found within the subject string.

local Amount = v:FindFirstChildWhichIsA("TextLabel") -- text label is equal to the amount of items the player has
if Amount then --Check if 'Amount' exists.
	local Number = string.match(Amount.Text, "^(%d+)x$") --Grab the number part from the text label's name.
	if Number then --Make sure 'Number' is not 'nil'.
		print(Number) --Output the value of 'Number'.
	end
end