# Modifying An Array

## Basic Operations

Arrays in OSL provide several methods for modification and access.

```javascript
arr = [1, 2, 3, 4]

// Accessing elements (1-indexed)
first = arr[1]
// 1
second = arr[2]
// 2

// Modifying elements
arr[1] = 10
// [10, 2, 3, 4]

// Getting length
length = arr.len
// Number of elements
```

## Adding and Removing Elements

```javascript
// Adding elements
void arr.append(5)
// Adds to end
void arr.prepend(0)
// Adds to beginning

// Removing elements
last = arr.pop()
// Removes and returns last element
first = arr.shift()
// Removes and returns first element
```

## Array Methods

```javascript
// Sorting
arr.sort()

// Swapping elements
arr.swap(1, 2)
// Swaps elements at indices 1 and 2

// Getting random element
random = arr.randomOf()

// Slicing arrays
slice = arr.trim(2, 4)
// Gets elements from index 2 to 4 inclusive

// Mapping over elements
doubled = arr.map(x -> x * 2)

// Fill array with value
numbers = (1 to 10).fill("hi")
// ["hi", "hi", "hi", "hi", "hi", "hi", "hi", "hi", "hi", "hi"]
```

## Array Merging

```javascript
// Using the ++ operator
arr1 = [1, 2]
arr2 = [3, 4]
combined = arr1 ++ arr2  // [1, 2, 3, 4]
```

## Important Notes

* Arrays are 1-indexed in OSL
* Most operations create new copies
* `.trim()` is used for array slicing
* Destructuring can skip elements using empty slots
* The `++` operator combines arrays
* Methods like `sort()` and `map()` return new arrays