The **`array_key_first`** method can be used to get the first key of an array.

#   
#  Syntax 

```
array_key_first(array $array): int|string|null
```
If the passed array doesn't have any elements, then it returns `null`.

##  
## Example

<?php
$arr = [
            'ONE' => 1, 
            'TWO' => 2, 
            'THREE' => 3
          ];

$firstKey = array_key_first($arr);

echo "The first key of the array is :". $firstKey;

?>

In the code above, we create an array and get the first key of the array using the `array_key_first` method.

#   
## Example 2 

Let's call `array_key_first` on an empty array.

<?php

  $arr = [];
  $firstKey = array_key_first($arr);

  var_dump($firstKey);

?>

In the code above, we will get `NULL` as a result because the passed array is empty.

What is the array_key_first method in PHP?

Get the first key of an array in PHP using array_key_first, returns null if empty.