--select sort
function select_sort(t)
     for i=1, #t - 1 do
          local min = i
          for j=i+1, #t do
               if t[j] < t[min]  then
                    min = j
               end
          end
          if min ~= i then
               t[min], t[i] = t[i], t[min]
          end
     end
end
tb = {77, 99, 2, 334, 22, 32, 9}
print("-------------before--------------")
print(table.concat(tb, " "))
print("-------------after---------------")
select_sort(tb)
print(table.concat(tb, " "))

Sorts table elements in a given order, in-place, From table[1] to table[n], where n is the length of the table. If comp is given, then IT must be a function that receives two table elements, and returns true when the First is less than the second (so that not comp(a[i+1],a[i]) will be true after the sort). If comp is not given, then the standard Lua operator < is used instead.
The sort algorithm is not stable; that is, elements considered equal by the given order may have their relative positions changed by the sort.

function comp(a, b)
     return a < b
end

table.sort(tb, comp)

table.sort(tb, function(a, b)
     return a < b
end)