What's the difference between pairs and ipars and how do they work?

pairs will iterate through every value in a table that isn't nil (the indices here don't matter, i just chose them randomly)

local tbl = {
    ok = true;
    [1] = "test";
    [2] = "O_O";
    stupid = nil;
    [4] = "test test";
    dumb = false;
}
for i, v in pairs(tbl) do
    print(i, v)
end

if you run that code using pairs, this will be the output (or at least all of these values will be in the output)

-- ok true
-- 1 test
-- 2 O_O
-- 4 test test
-- dumb false

as you can see, it went through every value in the table, except for stupid, since it was nil

on the other hand, ipairs only iterates through numeric indices, and will stop if there isn't an index for the next number

if you ran the same code, but with ipairs instead of pairs, this would be the output

-- 1 test
-- 2 O_O

that's because ipairs only went through the indices that were numbers, and it didn't print index 4 because the table skipped index 3