--- title: Chunky Monkey --- ![](//discourse-user-assets.s3.amazonaws.com/original/2X/a/aadd6bead83ab7d79a795c326f005a89e6ad81f5.png) ![:triangular_flag_on_post:](https://forum.freecodecamp.com/images/emoji/emoji_one/triangular_flag_on_post.png?v=3 ":triangular_flag_on_post:") Remember to use **`Read-Search-Ask`** if you get stuck. Try to pair program ![:busts_in_silhouette:](https://forum.freecodecamp.com/images/emoji/emoji_one/busts_in_silhouette.png?v=3 ":busts_in_silhouette:") and write your own code ![:pencil:](https://forum.freecodecamp.com/images/emoji/emoji_one/pencil.png?v=3 ":pencil:") ### ![:checkered_flag:](https://forum.freecodecamp.com/images/emoji/emoji_one/checkered_flag.png?v=3 ":checkered_flag:") Problem Explanation: Our goal for this Algorithm is to split `arr` (first argument) into smaller chunks of arrays with the length provided by `size` (second argument). There are 4 green checks (objectives) our code needs to pass in order to complete this Algorithm: 1. `(['a', 'b', 'c', 'd'], 2)` is expected to be `[['a', 'b'], ['c', 'd']]` 2. `([0, 1, 2, 3, 4, 5], 3)` is expected to be `[[0, 1, 2], [3, 4, 5]]` 3. `([0, 1, 2, 3, 4, 5], 2)` is expected to be `[[0, 1], [2, 3], [4, 5]]` 4. `([0, 1, 2, 3, 4, 5], 4)` is expected to be `[[0, 1, 2, 3], [4, 5]]` #### Relevant Links * Array.push() * Array.slice() ## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 1 The links above suggest to use `Array.push()`, so let's start by first creating a new array to store the smaller arrays we will soon have like this: ```javascript var newArray = []; ``` > _try to solve the problem now_ ## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 2 Next we'll need a `for loop` to loop through `arr`. > _try to solve the problem now_ ## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 3 Finally, we need a method to do the actual splitting and we can use `Array.slice()` to do that. The key to this Algorithm is understanding how a `for loop`, `size`, `Array.slice()` and `Array.push()` all work together. > _try to solve the problem now_ ## Spoiler Alert! ![warning sign](//discourse-user-assets.s3.amazonaws.com/original/2X/2/2d6c412a50797771301e7ceabd554cef4edcd74d.gif) **Solution ahead!** ## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Basic Code Solution: ```javascript function chunkArrayInGroups(arr, size) { var temp = []; var result = []; for (var a = 0; a < arr.length; a++) { if (a % size !== size - 1) temp.push(arr[a]); else { temp.push(arr[a]); result.push(temp); temp = []; } } if (temp.length !== 0) result.push(temp); return result; } ``` ![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") Run Code ### Code Explanation: * Firstly, we create two empty arrays called `temp` and `result`, which we will eventually return. * Our **for loop** loops until `a` is equal to or more than the length of the array in our test. * Inside our loop, we push to `temp` using `temp.push(arr[a]);` if the remainder of `a / size` is not equal to `size - 1`. * Otherwise, we push to `temp`, push `temp` to the `result` variable and reset `temp` to an empty array. * Next, if `temp` isn't an empty array, we push it to `result`. * Finally, we return the value of `result`. #### Relevant Links * Array.push() * For Loops ## ![:sunflower:](https://forum.freecodecamp.com/images/emoji/emoji_one/sunflower.png?v=3 ":sunflower:") Intermediate Code Solution: ```javascript function chunkArrayInGroups(arr, size) { // Break it up. var arr2 = []; for (var i = 0; i < arr.length; i+=size) { arr2.push(arr.slice(i , i+size)); } return arr2; } ``` ![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") Run Code ### Code Explanation: * First, we create an empty array `arr2` where we will store our 'chunks'. * The for loop starts at zero, increments by `size` each time through the loop, and stops when it reaches `arr.length`. * Note that this for loop does not loop through `arr`. Instead, we are using the loop to generate numbers we can use as indices to slice the array in the right locations. * Inside our loop, we create each chunk using `arr.slice(i, i+size)`, and add this value to `arr2` with `arr2.push()`. * Finally, we return the value of `arr2`. #### Relevant Links * Array.push() * Array.slice() * For Loops ## ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:") Advanced Code Solution: ```javascript function chunkArrayInGroups(arr, size) { // Break it up. var newArr = []; var i = 0; while (i < arr.length) { newArr.push(arr.slice(i, i+size)); i += size; } return newArr; } chunkArrayInGroups(["a", "b", "c", "d"], 2); ``` ![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") Run Code ### Code Explanation: * Firstly, we create two variables. `newArr` is an empty array which we will push to. We also have the `i` variable set to zero, for use in our while loop. * Our while loop loops until `i` is equal to or more than the length of the array in our test. * Inside our loop, we push to the `newArr` array using `arr.slice(i, i+size)`. For the first time it loops, it will look something like: newArr.push(arr.slice(1, 1+2)) * After we push to `newArr`, we add the variable of `size` onto `i`. * Finally, we return the value of `newArr`. #### Relevant Links * Array.push() * Array.slice() * While Loops ## ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:") Advanced Code Solution 2: ```javascript function chunkArrayInGroups(arr, size) { var newArr = []; while (arr.length) { newArr.push(arr.splice(0,size)); } return newArr; } ``` ![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") Run Code ### Code Explanation: * Firstly, we create a variable. `newArr` is an empty array which we will push to. * Our `while` loop loops until the length of the array in our test is not 0. * Inside our loop, we push to the `newArr` array using `arr.splice(0, size)`. * For each iteration of `while` loop, it deletes `size` number of elements from the front of `arr` and push them as an array to `newArr`. * Finally, we return the value of `newArr`. #### Relevant Links * Array.push() * Array.splice() * While Loops ## ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:") Advanced Code Solution 3: ```javascript function chunkArrayInGroups(arr, size) { if (arr.length <= size){ return [arr]; } else { return [arr.slice(0,size)].concat(chunkArrayInGroups(arr.slice(size),size)); } } ``` ![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") Run Code ### Code Explanation: * Array smaller than size is returned nested. * For any array larger than size, it is split in two. First segment is nested and concatenated with second segment which makes a recursive call. #### Relevant Links * Recursion * Array.splice() ## ![:clipboard:](https://forum.freecodecamp.com/images/emoji/emoji_one/clipboard.png?v=3 ":clipboard:") NOTES FOR CONTRIBUTIONS: * ![:warning:](https://forum.freecodecamp.com/images/emoji/emoji_one/warning.png?v=3 ":warning:") **DO NOT** add solutions that are similar to any existing solutions. If you think it is **_similar but better_**, then try to merge (or replace) the existing similar solution. * Add an explanation of your solution. * Categorize the solution in one of the following categories — **Basic**, **Intermediate** and **Advanced**. ![:traffic_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/traffic_light.png?v=3 ":traffic_light:") * Please add your username only if you have added any **relevant main contents**. (![:warning:](https://forum.freecodecamp.com/images/emoji/emoji_one/warning.png?v=3 ":warning:") **_DO NOT_** _remove any existing usernames_) > See ![:point_right:](https://forum.freecodecamp.com/images/emoji/emoji_one/point_right.png?v=3 ":point_right:") **`Wiki Challenge Solution Template`** for reference.