array_is_list() │ WP 6.5.0

Checks if an array is a list.

An array is considered a list if its keys consist of consecutive numbers from 0 to count($array)-1.

This is a polyfill for the PHP function array_is_list(), added in PHP 8.1.

No Hooks.

Returns

true|false. true - the array is a list, false - it is not.

Usage

array_is_list( $arr );
$arr(array) (required)
The array to check.

Examples

0

#1 Example of using array_is_list() 

array_is_list( [] ); // true
array_is_list( [ 'apple', 2, 3 ] ); // true
array_is_list( [ 0 => 'apple', 'orange' ] ); // true

// The array does not start with 0
array_is_list( [ 1 => 'apple', 'orange' ] ); // false

// The array keys are not in order
array_is_list( [ 1 => 'apple', 0 => 'orange' ] ); // false

// The array keys are not integers
array_is_list( [ 0 => 'apple', 'foo' => 'bar' ] ); // false

// Non-sequential keys
array_is_list( [ 0 => 'apple', 2 => 'bar' ] ); // false

Notes

Changelog

Since 6.5.0 Introduced.

array_is_list() code WP 6.8.1

wp-includes/compat.php 
function array_is_list( $arr ) {
	if ( ( array() === $arr ) || ( array_values( $arr ) === $arr ) ) {
		return true;
	}

	$next_key = -1;

	foreach ( $arr as $k => $v ) {
		if ( ++$next_key !== $k ) {
			return false;
		}
	}

	return true;
}

Supporting (helper utility auxiliary)

PHP Polyfills (analogues PHP functions replacement)

Checks