How can I use in pairs?

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#21

There’s such thing as a mixed table. This is not a very reliable check. typeof is also ridiculously slow, so I’d recommend type where possible. Also, please don’t edit in a reply that answers a reply further down in the thread, it breaks the continuity of the thread.

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#22

The typeof was just because I’m used to using that for validating Roblox-specific datatypes, type should be used here probably.

Obviously not reliable, that’s the reason why I said it would only work for defining ‘typical’ tables (where it is either a dictionary or an array, was only a quick edit to my post), for example using that algorithm it would print {} as a dictionary which it technically isn’t.

I left an extra end there by mistake

Anyways, since I don’t have access to Studio, I wrote this in Lua 5.3.5


local tab = {1, nil, 1}

local function nilfound(t)

local i = 0
for _, _ in pairs(t) do
    i = i + 1
end

if i - #tab ~= 0 then return true end

end

setmetatable(tab, {
    __tostring = function(self)
     if nilfound(self) then return "nil found, cannot perform operation" end 
     local indexes, result, numericalindex = {}, nil, nil
           for k, _  in pairs(self) do 
               if type(k) == "number" then numericalindex = true end
               if type(k) ~= "number" and numericalindex then return "mixed table" end
               table.insert(indexes, k)
           end 

           if #indexes == 0 then return "empty table" end
           
           if #self ~= #indexes then result = "dictionary" 
           else
               result = "array"    
           end
           
        return result
     end


})

print(tab) --> cannot perform operation

Edit:

+This code was optimized to work better for various cases.

Just adding this here: typeof was optimized in Luau

@ zeuxcg

Optimize typeof() to run ~6x faster. It used to be that type() was much faster than typeof() but they now should be more or less comparable.

1 Like
Check whether table contains nil
How can I find things that aren't in the table?
#24

???

Where in my post does it say a table is not a valid type, or that an array and a table are different types?

I was only suggesting that saying
type(t)
would return anything different from what calling type(t) would return where t is either a table or array is incorrect.

I’m just saying even if it were an array, type(t) would still return “table” so I won’t say that’s a reliable check to differentiate between a numerically indexed table or a dictionary.

1 Like
#25

Keep in mind that even this convoluted of a check will still consider local tab = {1, 2, nil, 3, [true] = "there"} an array, so there’s not an ideal way to check for this.

4 Likes
#26

Considers almost every case possible, if the table contains nil then it’ll not do anything because it’s not any of the three, (for the nil part, I had to resort to the forum and an unexpectedly simple function).

1 Like
#27

Hey i have a question, how i can get only one value, like

for i,v in pairs(script.Workspace:GetChildren()) do 
		if v:IsA("BasePart") then
			print(v.Name) -- but only get the name of the first value it found
		end
1 Like
#28

Iterating isn’t always necessary, ::GetChildren() returns an array, so just use the first returned object

local firstPart = workspace:GetChildren()[1]
if firstPart:IsA("BasePart") then 
    print(firstPart.Name) 
end

But if you want it to keep iterating until a BasePart is found, hence print the name only once:

for _,v in ipairs(workspace:GetChildren()) do 
		if v:IsA("BasePart") then
			print(v.Name) 
           return -- if the eval returns true, return end and stop iterating
		end
    end

Also, how on Earth did you manage to parent the workspace to a script!?
I believe you meant to instead just use the shorthand workspace, or game.Workspace.

2 Likes
#29

Thanks this help me a loot [quote=“XxELECTROFUSIONxX, post:28, topic:626905”]
Also, how on Earth did you manage to parent the workspace to a script!?
I believe you meant to instead just use the shorthand workspace, or game.Workspace
[/quote]

Srry I copy this from a script I have and change this a bit, but again thanks a loot

2 Likes