Typed Arrays

Part of the Introduction To Luau section of Coddy's Lua journey. Lesson 13 of 73.

Typed arrays are one of Luau's most useful features for organizing multiple values while keeping type safety.

In Lua, an array is just a table with values at positions 1, 2, 3, … — and it will happily hold a number, a string and a boolean all at once. Luau lets you declare that a table should only contain elements of one type, using the {Type} syntax:

local numbers: {number} = {1, 2, 3, 4, 5}
local names: {string} = {"Alice", "Bob", "Charlie"}
local flags: {boolean} = {true, false, true}

When you declare a typed array, Luau's type checker enforces that only values of the declared type go in. Insert a string into a {number} array and you get a type error while editing — before the code ever runs:

local scores: {number} = {85, 90, 78}
table.insert(scores, "oops") -- ✗ type error: string is not a number

Everything you already know about Lua tables still applies: arrays are 1-based (scores[1] is the first element), #scores is the length, and table.insert / table.remove work as usual. The annotation adds safety, not new runtime behavior.

Challenge

Easy

Create a typed array named scores that can only hold numbers, initialized with 85, 92 and 78.

Create a second typed array named studentNames that can only hold strings, initialized with "Alice", "Bob" and "Charlie".

Then print, each on its own line:

the first score
how many scores there are (use #)
the second student name

Try it yourself

-- Write code here
-- 1) declare scores: {number} and studentNames: {string}
-- 2) print first score, the scores count, and the second name

Test yourself

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