ตารางในรูปแบบอาร์เรย์

local colors = {"red", "green", "blue"}
print(colors[1])   -- red
print(colors[2])   -- green
print(colors[3])   -- blue
print(colors[0])   -- nil (no index 0)
print(#colors)     -- 3 (length operator)

local stack = {}
table.insert(stack, "first")
table.insert(stack, "second")
table.insert(stack, "third")
print(#stack)          -- 3

table.insert(stack, 2, "inserted")
print(stack[2])        -- inserted

local removed = table.remove(stack, 1)
print(removed)         -- first
print(stack[1])        -- inserted

local stack = {}

-- Push
table.insert(stack, 10)
table.insert(stack, 20)
table.insert(stack, 30)

-- Pop
print(table.remove(stack))  -- 30
print(table.remove(stack))  -- 20
print(#stack)               -- 1

local head, tail = 1, 0
local queue = {}

local function enqueue(v)
  tail = tail + 1
  queue[tail] = v
end

local function dequeue()
  if head > tail then return nil end
  local v = queue[head]
  queue[head] = nil
  head = head + 1
  return v
end

enqueue("a"); enqueue("b"); enqueue("c")
print(dequeue())  -- a
print(dequeue())  -- b

local t = {10, 20, 30, 40, 50}
print(#t)   -- 5

-- Safe for dense arrays
for i = #t, 1, -1 do
  io.write(t[i] .. " ")
end
print()  -- 50 40 30 20 10

local src = {10,20,30,40,50,60}

-- Manual slice
local function slice(t, from, to)
  local result = {}
  for i = from, to do
    result[#result+1] = t[i]
  end
  return result
end

local sub = slice(src, 2, 4)
print(sub[1], sub[2], sub[3])  -- 20  30  40

local function reverse(t)
  local n = #t
  for i = 1, math.floor(n / 2) do
    t[i], t[n - i + 1] = t[n - i + 1], t[i]
  end
end

local arr = {1, 2, 3, 4, 5}
reverse(arr)
for _, v in ipairs(arr) do
  io.write(v .. " ")
end
print()  -- 5 4 3 2 1

local function concat(a, b)
  local result = {}
  for _, v in ipairs(a) do result[#result+1] = v end
  for _, v in ipairs(b) do result[#result+1] = v end
  return result
end

local merged = concat({1,2,3}, {4,5,6})
for i, v in ipairs(merged) do
  io.write(v .. " ")
end
print()  -- 1 2 3 4 5 6

local function flatten(t, result)
  result = result or {}
  for _, v in ipairs(t) do
    if type(v) == "table" then
      flatten(v, result)
    else
      result[#result+1] = v
    end
  end
  return result
end

local nested = {1, {2, 3}, {4, {5, 6}}, 7}
local flat = flatten(nested)
print(table.concat(flat, ", "))  -- 1, 2, 3, 4, 5, 6, 7

local function toSet(arr)
  local set = {}
  for _, v in ipairs(arr) do set[v] = true end
  return set
end

local nums = {3,1,4,1,5,9,2,6,5,3}
local set = toSet(nums)
local unique = {}
for k in pairs(set) do unique[#unique+1] = k end
table.sort(unique)
print(table.concat(unique, " "))  -- 1 2 3 4 5 6 9