We can omit all ipairs and pairs in for-loop

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#1

I’ve found that for the vast majority of for loops, we don’t need to differentiate between ipairs and pairs. This is weird and hard to differentiate for new developers, and I think it’s counter-intuitive and bad design. If we need to differentiate, we can decide whether the index is a number or a letter in the for loop.According to this Luau Recap: May 2022 new Luau update, can I delete all the ipairs and pairs in my for loop?

1 Like
#2

You can. there may be issues for tables with non-sequential number keys, but these tables have a lot of problems either way.

#3

Yes you can, just keep in mind that there’s a slight nuance with generalized iteration.

local t = {1, 2, 3, a = 1, b = 2, c = 3}
t[2] = nil

for i, v in pairs(t) do --Iterates over all key/value pairs.
	print(i, v)
end

--1 1
--3 3
--a 1
--b 2
--c 3

for i, v in ipairs(t) do --Iterates over all index/value pairs stopping at the first empty slot (nil value).
	print(i, v)
end

--1 1

for i, v in t do --Iterates over the array part (stopping at the first empty slot) and then iterates over the hash part.
	print(i, v)
end

--1 1
--a 1
--b 2
--c 3

Mixed tables (tables with array and hash parts) are discouraged and Roblox’s own API methods will only ever return pure arrays/pure hashes.

4 Likes
#4

Thank you for your detailed reply! I got a lot of details that I didn’t notice!