array_key_first
Returns the first key of an array.
Syntax
array_key_first(array $array): int|string|nullParameters
| Parameter | Type | Description |
|---|---|---|
| $array | array | The source array. |
Return value
int|string|nullThe first key, or `null` for an empty array.
Examples
The first and the last key:
<?php
$prices = ['tea' => 250, 'coffee' => 400, 'juice' => 180];
echo array_key_first($prices), ' ', array_key_last($prices);Output:
tea juiceThe last element of a list without changing the array:
<?php
$numbers = [10, 20, 30];
echo $numbers[array_key_last($numbers)];Output:
30Notes
The companion array_key_last() returns the last key. Neither modifies the array, unlike array_shift() and array_pop().
See also
- array_keys — Returns all the keys of an array.
- array_pop — Removes the last element of an array and returns it.
In the tutorial
- Arrays — Lists and associative arrays in PHP — creating, changing, iterating and useful functions.