Lua Academy · Lesson

Nested Tables and Structured Data

Build nested structures and access deep fields.

Nested Table Basics

Tables can contain other tables as values, creating arbitrarily deep structures. Access nested fields by chaining dots or brackets. Missing intermediate tables cause errors — always ensure parent tables exist before accessing deep fields.

local company = {
  name = "CoddyKit",
  address = {
    city = "Istanbul",
    country = "Turkey",
    zip = "34000"
  },
  employees = 25
}

print(company.name)            -- CoddyKit
print(company.address.city)    -- Istanbul
print(company["address"]["zip"]) -- 34000

Safe Deep Access

Accessing a field on a nil value crashes with "attempt to index a nil value". Guard against this with the and short-circuit: t and t.a and t.a.b. Some codebases define a get(t, ...) helper that safely traverses a chain of keys.

local function get(t, ...)
  local cur = t
  for _, key in ipairs({...}) do
    if type(cur) ~= "table" then return nil end
    cur = cur[key]
  end
  return cur
end

local data = {user = {profile = {age = 30}}}
print(get(data, "user", "profile", "age"))    -- 30
print(get(data, "user", "missing", "field"))  -- nil

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