I am trying to create an inventory system and I need to know if there is more than one of the same item in the inventory so the inventory can look functional and organized.

This is what I have tried so far:

inventoryEvent.OnClientEvent:Connect(function(ItemName)

    local count = 0
    for _,v in pairs(player.Inventory:GetChildren()) do
	    if v.Name == ItemName and count > 1 then
		    print("There is more than one.")
		    count = count + 1
	    end
    end

But this does not work because every time inventoryEvent is fired then count will be set back to 0. So it seems I somehow need to make the script remember what the count was for the item.

I am thinking I can do that by adding a NumberValue under the item added to the inventory and changing the value each time a duplicate of the item is added to the inventory. But I still need the script be able to detect when there is more than one of the same item in the inventory.

How can I accomplish this?

I mean, you could use a NumberValue object, but that's adding an unnecessary layer of complexity and things to keep track of.

So the Solution?

Instead of using NumberValues and for loops, it would be much nicer to create a dictionary table that keeps track of which items the user has, and how many of them. Here's an implementation:

-- a dictionary record of the items the user has received
local itemsOwned = {
--[[
	Example data:

	["Item one"] = 3,	-- user has 3 of these
	["Item two"] = 7,	-- user has 7 of these
	["Item three"] = 0,	-- user has 0 of these
]]
}

inventoryEvent.OnClientEvent:Connect(function(ItemName)

	-- get item data from the table if it exists
	local itemData = itemsOwned[itemName]

	-- case where user receives item for the first time
	if not itemData then

		-- the user now has 1 of this item
		itemsOwned[itemName] = 1
		print("The user has received a new item!")

	-- case where user already has the item
	elseif itemData > 0 then

		itemsOwned[itemName] = itemData + 1
		print("The user already has this item!")

	end

end)

How it Works

First Time Receiving a new Item

So, upon receiving a new item for the first time, that item name will not exist in the itemsOwned table.

	...

	-- get item data from the table if it exists
	local itemData = itemsOwned[itemName]

	-- case where user receives item for the first time
	if not itemData then

	...

We then create a new entry for it and set it equal to 1 (to represent that the user owns only one of those items).

		-- the user now has 1 of this item
		itemsOwned[itemName] = 1
		print("The user has received a new item!")

Receiving an Already Owned Item

If the user already owns the item, that will trigger the else clause and bring us to the next branch of our code:

	-- case where user already has the item
	elseif itemData > 0 then

Since the user already owns the item, itemData already exists and we can simply increment it's value.

	itemsOwned[itemName] = itemData + 1
	print("The user already has this item!")

Hopefully this makes sense. Let me know if you have any questions.

I think because you added and count > 1 in the condition, the count += 1 never runs, therefore the count stays 0, simply remove that condition.

inventoryEvent.OnClientEvent:Connect(function(itemName)
	local count = 0

	for _, item in pairs(player.Inventory:GetChildren()) do
		if v.Name == itemName then
			count += 1
		end
	end

	if count > 1 then
		--there is more than one of the same item in the inventory
	end
end)