For PHP < 7.3.0:
<?php
if (!function_exists('array_key_first')) {
/**
* Gets the first key of an array
*
* @param array $array
* @return mixed
*/
function array_key_first(array $array)
{
if (count($array)) {
reset($array);
return key($array);
}
return null;
}
}
echo array_key_first([
'foo' => 'value1',
'bar' => 'value2',
]);
// Output: foo
array_key_first
(PHP 7 >= 7.3.0)
array_key_first — Gets the first key of an array
Description
Get the first key of the given array without affecting
the internal array pointer.
Parameters
-
array -
An array.
Return Values
Returns the first key of array if the array is not empty;
NULL otherwise.
Examples
Example #1 Basic array_key_first() Usage
<?php
$array = ['a' => 1, 'b' => 2, 'c' => 3];
$firstKey = array_key_first($array);
var_dump($firstKey);
?>
The above example will output:
string(1) "a"
See Also
- array_key_last() - Gets the last key of an array
- reset() - Set the internal pointer of an array to its first element
add a note
User Contributed Notes 3 notes
mail at vitalyart dot ru ¶
3 months ago
mirko dot pagliai at gmail dot com ¶
1 month ago
It's much simpler than the examples already posted by other users (without ridiculous foreach cycles, LoL).
For PHP < 7.3.0:
<?php
if (!function_exists('array_key_first')) {
/**
* Gets the first key of an array
*
* @param array $array
* @return mixed
*/
function array_key_first(array $array)
{
return $array ? array_keys($array)[0] : null;
}
@manzoorwanijk ¶
3 months ago
For PHP < 7.3.0 :
<?php
if ( ! function_exists( 'array_key_first' ) ) {
/**
* Polyfill for array_key_first() function added in PHP 7.3.
*
* Get the first key of the given array without affecting
* the internal array pointer.
*
* @param mixed $array An array
*
* @return mixed The first key of array if the array is not empty; NULL otherwise.
*/
function array_key_first( $array ) {
$key = null;
if ( is_array( $array ) ) {
foreach ( $array as $key => $value ) {
break;
}
}
return $key;
}
}
?>
