# deleteAt

## Category
Array

## Arity
**Binary** — `<array> deleteAt <index>`.

```
<array> deleteAt <number>
```

## Description
Removes the element at the given zero-based index from the array. Returns the deleted value. If the index is out of range, returns `nil` and the array is unchanged.

## How It Works
Checks bounds. If valid, retrieves the element at `index`, removes it from the list (shifting subsequent elements left), and returns the retrieved value. O(n) due to shift.

## Usage

### Remove by index
```sqf
_arr = ["a", "b", "c", "d"];
_removed = _arr deleteAt 1;    // returns "b", _arr is ["a","c","d"]
```

### Pop from front (queue dequeue)
```sqf
_queue = [1, 2, 3, 4];
_next = _queue deleteAt 0;     // returns 1, _queue is [2,3,4]
```

### Pop from back
```sqf
_stack = [1, 2, 3];
_top = _stack deleteAt (count _stack - 1);  // returns 3
```

### Safe delete (guard out-of-range)
```sqf
if (_index >= 0 && _index < count _arr) then {
    _val = _arr deleteAt _index;
};
```

### Remove matching element
```sqf
_removeByValue = {
    params ["_arr", "_val"];
    _idx = _arr find _val;
    if (_idx != -1) then { _arr deleteAt _idx };
};
```

## Thread Safety
**Not thread-safe**. Array must belong to the current scheduler.

## See Also
- [deleteRange](deleteRange.md) — remove multiple elements
- [pushBack](pushBack.md) — append element
- [select](select.md) — element access
- [find](find.md) — find element index
- [resize](resize.md) — change array size