[Concept Entry] Luau: Arrays Codecademy#3203 (Codecademy#3546)

* [Concept Entry] Luau: Arrays Codecademy#3203

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update content/luau/concepts/arrays/arrays.md

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* Update arrays.md

---------

Co-authored-by: Caupolican Diaz <[email protected]>
Co-authored-by: SSwiniarski <[email protected]>

content/luau/concepts/arrays/arrays.md

@@ -0,0 +1,118 @@
+---
+Title: 'Arrays'
+Description: 'Arrays are used to store ordered collections of data.'
+Subjects:
+  - 'Computer Science'
+Tags:
+  - 'Tables'
+  - 'Arrays'
+  - 'Iterators'
+CatalogContent:
+  - 'learn-lua'
+  - 'paths/computer-science'
+---
+
+**Arrays** are a type of container for storing data in ordered collections. Luau, a lightweight and efficient scripting language, implements arrays using a single structure known as a table.
+
+Arrays are versatile data structures capable of storing various data types, and values can be retrieved or modified using the conventional indexing syntax `[]`. To clear an array, the elements are set to `nil`.
+
+## Syntax
+
+Luau allows for the creation of arrays using curly braces `{}`. Unlike some programming languages that start array indexing from `0`, in Luau, by default, the first element in an array is designated as index `1`. However, Luau provides the flexibility to create arrays with custom indices as needed.
+
+```lua
+a = {5};  -- An array with single elemnent
+
+print(a[1]) -- This will return 5
+print(a[2]) -- This will return nil because the index is out of range
+```
+
+The array created above contains one element only with the value `5`, it can be accessed by passing the index value `1`. However, if a value is passed out of the range of the array, the code will return `nil`. This is because `nil` refers to missing data.
+
+## Accessing Elements
+
+To access an array element, the desired value is called by its _index_. For example, to reference a value from the following array:
+
+```lua
+a = {
+    [1] = "a",
+    [2] = "b",
+    [3] = "c"
+}
+```
+
+In this array, elements are indexed from 1 to 3. To print `b`, reference it by its assigned index, which is 2.
+
+This indexing method works for all elements in an array. This also works with dictionaries, but instead the assigned _key_ must be used to retrieve a value. A _key_ is essentially an _index_ with the only difference being that a _key_ may be assigned as any type, while an _index_ must be a number.
+
+For example:
+
+```lua
+dictionary = {
+    ["A"] = "Apple",
+    ["B"] = "Banana",
+    ["C"] = "Cat"
+}
+
+print(dictionary["C"]) -- "Cat"
+```
+
+It's important to note that in Lua (and Luau), when accessing a dictionary or array using an index or key, Luau returns the associated value, not the index or key itself.
+
+## Replacing Elements
+
+Values can be reassigned in Luau arrays by specifying the index and providing a new value, as shown below:
+
+```lua
+a[2] = "c" -- Now the object at index is 2 is c instead of b
+```
+
+To remove an element, simply reassign the index to `nil`.
+
+```lua
+a[2] = 'nil'
+```
+
+## Getting the Length of an Array
+
+Frequently, it's necessary to determine the length or size of an array. In Luau, use the `#` symbol before an array to retrieve its length.
+
+> **Note:** This syntax returns the last index of the array, which may not always be equivalent to the actual size of the array.
+
+```lua
+names = {"Alice", "Bob", "Charlie", "David"} -- Let's consider an array of names
+
+local size = #names -- We can use the '#' symbol to determine the size of the 'names' array
+
+for i = 1, size do
+  print(names[i]) -- Access and print each element of the array
+end
+```
+
+## Adding and Removing Elements
+
+Elements can be added to the end of an array using the `table.insert()` function:
+
+```lua
+table.insert(a, 6) -- Adds the value 6 to the end of array 'a'
+```
+
+To remove an element from an array, use the `table.remove()` function:
+
+```lua
+table.remove(a, 3) -- Removes the element at index 3 from array 'a'
+```
+
+## Multi-Dimensional Arrays
+
+Luau supports multi-dimensional arrays, which are arrays of arrays. They can be created like this:
+
+```lua
+matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
+```
+
+Accessing elements in a multi-dimensional array requires using multiple sets of square brackets:
+
+```lua
+value = matrix[2][3] -- Accesses the element at row 2, column 3 of the matrix
+```