--- title: "Loops and arrays" url: /docs/en-us/tutorials/fundamentals/coding-5/loops-and-arrays last_updated: 2026-08-13T00:14:54Z description: "Learn how to iterate, or go through, arrays in Luau using loops." --- # Loops and arrays **Arrays** can be combined with loops, such as **while** and **for**, to repeat the same code for each indexed value. For example, teleporting each player in an array to a new place or making an array of parts catch fire. To explore looping through arrays, create a disappearing bridge path where parts are placed into an array and then made to vanish one by one. ## Loop through an array For the project, find or create a set of three parts to make disappear. The parts must all be anchored. 1. Create three parts. Name the parts in the order they should disappear, Part1, Part2, Part3. 2. In ServerScriptService, insert a new script and create an array to store the parts.```lua local pathArray = { } ``` 3. On a single line each, type the name of the parts in the order they should disappear. Using a new line for each value makes it easier to read.```lua local pathArray = { workspace.Part1, workspace.Part2, workspace.Part3, } ``` ### Use a for loop with an array Use a for loop to go through the array and control how fast the parts should disappear in the order the parts are indexed within the array. 1. To control how often a part disappears in seconds, create a variable named `VANISH_RATE`. For testing, it's best to keep it to a small number.```lua local VANISH_RATE = 1.5 local pathArray = { workspace.Part1, workspace.Part2, workspace.Part3 } ``` > **Info:****Constants** are variables that shouldn't be changed by any other code in the script. They're likely to need adjusting and are put at the top of the script in `ALL_CAPS` to make them easy to spot. 2. Create a for loop with the following: **Start:** `partIndex = 1`, the index of the first value in the array. **End:** `#pathArray`, the size of that array.```lua for partIndex = 1, #pathArray do end ``` 3. So there's a delay before a part disappears, in the loop, add a `Library.task.wait()` using `VANISH_RATE`.```lua for partIndex = 1, #pathArray do task.wait(VANISH_RATE) end ``` 4. To get a part to disappear, create a new variable named `whichPart` and set it equal to `partsArray[partIndex]`. Then, to disappear that part, set it's `CanCollide` property to false and `Transparency` to 1.```lua for partIndex = 1, #pathArray do task.wait(VANISH_RATE) local whichPart = pathArray[partIndex] whichPart.CanCollide = false whichPart.Transparency = 1 end ``` 5. Check that parts of the path disappear over time. ### Troubleshooting tips If the bridge doesn't disappear, check the possible issues below: **Issue:** Parts disappear too fast or are all gone at the start. - Depending on how fast your character loads into the game, the first parts may already be invisible. To address this, add a small wait, such as `task.wait(2)`, at the start of the script. ### Code the second loop Right now, the parts disappear forever. To make them reappear, create a second for loop that will go through each part and instantly make each piece walkable. 1. After the first loop, add a `Library.task.wait()` to create a short delay before the path reappears.```lua for partIndex = 1, #pathArray do task.wait(VANISH_RATE) local whichPart = pathArray[partIndex] whichPart.CanCollide = false whichPart.Transparency = 1 end task.wait(1) ``` 2. **On your own**, try coding a second for loop that makes the path usable again by changing each part's CanCollide property to true and Transparency to 0. When finished, check your work against the code below.```lua -- Reset the path by making all parts walkable again for partIndex = 1, #pathArray do local whichPart = pathArray[partIndex] whichPart.CanCollide = true whichPart.Transparency = 0 end ``` > **Warning:** Unanchored parts will fall through the baseplate when CanCollide is false. If the parts aren't reappearing, and there are no Output errors, anchor the parts and test again. 3. Test the project to confirm that once all parts disappear, they come back. ## Repeat with a while loop The parts disappear and reappear, but only once. To make the code keep repeating, nest all of the code within a while loop. 1. At the bottom of the script, create a new while true do loop. Then, **move both** for loops into the while loop.```lua while true do -- Make a part disappear from the array in order for partIndex = 1, #pathArray do task.wait(VANISH_RATE) local whichPart = pathArray[partIndex] whichPart.CanCollide = false whichPart.Transparency = 1 end -- Wait for a second before making the path reappear task.wait(1) -- Reset the path by making all parts walkable again for partIndex = 1, #pathArray do local whichPart = pathArray[partIndex] whichPart.CanCollide = true whichPart.Transparency = 0 end end ``` 2. Check that once all parts disappear, they reappear. A finished version of the project can be downloaded. ```lua local VANISH_RATE = 1.0 local pathArray = { workspace.Part1, workspace.Part2, workspace.Part3, } while true do -- Make a part disappear from the array in order for partIndex = 1, #pathArray do task.wait(VANISH_RATE) local whichPart = pathArray[partIndex] whichPart.CanCollide = false whichPart.Transparency = 1 end -- Wait for a second before making the path reappear task.wait(1.0) -- Reset the path by making all parts walkable again for partIndex = 1, #pathArray do local whichPart = pathArray[partIndex] whichPart.CanCollide = true whichPart.Transparency = 0 end end ``` ## Arrays and ipairs() `ipairs()` is used with **arrays**. The "i" in `ipairs()` stands for "index." ipairs() can be used to quickly repeat an operation on a lot of objects, like, say, a folder full of parts. This will be demonstrated by quickly adding particles to a whole folder of parts. 1. In Workspace, create a folder named PartsFolder. Add as many parts as you like. 2. In ServerScriptService, Create a new script and reference the folder. 3. Use GetChildren() to automatically get an array listing all the objects in the folder.```lua local partsFolder = workspace.PartsFolder -- Gets an array listing the parts in PartsFolder local partsArray = partsFolder:GetChildren() ``` 4. Use `in ipairs(ArrayToUse)` with the for loop to go through partsArray and add particles.```lua -- Gets an array listing the parts in PartsFolder local partsArray = partsFolder:GetChildren() -- Adds particles to every part in the array for index, part in ipairs(partsArray) do local particles = Instance.new("ParticleEmitter") particles.Parent = part end ``` Playtest and watch the particles float up from every part in the folder. ## Summary Loops can be combined with arrays to work with any number of values quickly. If you want to have exact control over what happens to a few parts and in what order, an array must be hard-coded with specific values. To work with many parts where order doesn't matter, GetChildren() can create an array of an object's children. Utilizing `ipairs()`, the list can be quickly iterated over without knowing the array's size.