Difference between pairs and just the normal for k, v in array do

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#1

I’m not sure if it actually improves the speed or not because I know when you use :GetChildren()) it returns a table of the instance, same with :GetDescendants(), etc., if it really does improves the speed then I might have to change most of the for loop that I have used.

function self.GetPlayerAssets()
	local images = Player:FindFirstChild("Images")
	local sounds = Player:FindFirstChild("Sounds")

	for _, imageLabel in images:GetChildren() do
		print(imageLabel)
	end
		
	for _, imageLabel in pairs(images:GetChildren()) do
		print(imageLabel)
	end
end
#2

Okay so I ran a benchmark and the first option (__iter metamethod) seems to be very slightly faster in general, but not enough to warrant a change in entire codebase:

image
image605×771 43.2 KB

1 Like
#3

I also did some test but I don’t know if this is even called testing, I’d say there are no difference.

Code 
repeat wait(1) until game:IsLoaded()

game.Players.LocalPlayer.CharacterAdded:Wait()

local array = {}
local round = math.round
local insert = table.insert
local arrayTimeAverage = {}
local parisTimeAverage = {}

for i = 1, 50000000 do
	insert(array, i)
end

function checking(i)
	if i then
		local k = i + i
		
		if i + i == k then
			k = i
		end
	end
end

function arrayTest()
	local delta = tick()
	
	for _, i in array do
		checking(i)
	end
	
	return round((tick() - delta) * 1000)
end

function pairsTest()
	local delta = tick()
	
	for _, i in pairs(array) do
		checking(i)
	end
	
	return round((tick() - delta) * 1000)
end

function getAverageTime(timeArray)
	local average = 0
	
	for _, delta in timeArray do
		average += delta
	end
	
	average /= #timeArray
	
	return average
end

for i = 1, 5 do
	local timeDiff = arrayTest()
	
	insert(arrayTimeAverage, timeDiff)
	
	print(string.format("Array Time: %ims", timeDiff))
	wait(1)
end

print(string.format("Average Time: %ims", getAverageTime(arrayTimeAverage)))

for i = 1, 5 do
	local timeDiff = pairsTest()
	
	insert(parisTimeAverage, timeDiff)
	
	print(string.format("Pairs Time: %ims", timeDiff))
	wait(1)
end

print(string.format("Average Time: %ims", getAverageTime(parisTimeAverage)))

Array Time: 1257ms 
Array Time: 1271ms
Array Time: 1259ms 
Array Time: 1255ms 
Array Time: 1253ms 
Average Time: 1259ms 

Pairs Time: 1252ms 
Pairs Time: 1256ms
Pairs Time: 1255ms
Pairs Time: 1252ms
Pairs Time: 1254ms
Average Time: 1253ms