pairs(t)

Returns three values: the next function, the table t, and null, so that the construction

for k,v in pairs(t) do body end

will iterate over all key–value pairs of table t.

See function next for the caveats of modifying the table during its traversal.

Example

sum = 0
t = { 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 }
for key, value in pairs(t) do
    if key % 2 == 0 then 
        sum = sum + value 
    end
end