WHAT is happening when I set a table[key] to nil?

[M78zhaoritian]

Hello everyone,

I would like to share an issue I encountered while testing my game related to pet data on the client side. After a thorough investigation, I noticed inconsistencies in the results when I set pets[index] to nil, the pets table sometimes changes after my for-loop.

Firstly, I have noticed that passing a table through a remote event will perform like this:

local a = {
    [1] = 1,
    [2] = nil,
    [3] = nil,
    [4] = 4
}

remoteEvent:FireClient(player, a)

--[[ What we receive on the client is exactly the same as `a` ]]--

local b = {
    [1] = 1,
    [4] = 4
}

remoteEvent:FireClient(player, b)

--[[ on client is
    b = {
        [1] = 1
    }

    b[4] is gone
]]--

Here is the code I used:

In some cases, the code executes correctly, as shown in the following image:

However, in other cases, it produces incorrect results. When I pass the modified table to the client, all data after the first nil value is lost. This can be seen in the following images:

I am puzzled as to why the same operation produces different results. Could someone provide insight into this issue? Any help would be greatly appreciated.

Thank you!

[ImInversed]

table.remove should solve your issue.

table.remove(array, index)

I believe arrays cut every value after there is a gap between indexes.

[desinied]

Just wanted to give supporting information from Roblox Staff about this exact edge case

@Tiffblocks

Here’s a visual example of why table[index] = nil might not be what you want.

local t = { 1, 2, 3, 4, 5 }

t[3] = nil --> t == { 1, 2, nil, 4, 5 }
-- If you used table.remove instead, the table would turn into { 1, 2, 4, 5 }.

for index, value in ipairs(t) do
    print(value)
end
--> 1
--> 2
--> (loop stops)

table.remove will shift the remaining values after the removed index down one, to prevent the table from having nil holes in it. ipairs and # will not give you the entire contents of the array back if you have holes in your table.

Table.remove or table[index] = nil

Here’s a visual example of why table[index] = nil might not be what you want. local t = { 1, 2, 3, 4, 5 } t[3] = nil --> t == { 1, 2, nil, 4, 5 } -- If you used table.remove instead, the table would turn into { 1, 2, 4, 5 }. for index, value in ipairs(t) do print(value) end --> 1 --> 2 --> (loop stops) table.remove will shift the remaining values after the removed index down one, to prevent the table from having nil holes in it. ipairs and # will not give you the entire contents of the a…