ARRAY_KEY_EXISTS

1. ARRAY_KEY_EXISTS

array_key_exists — Checks if the given key or index exists in the array

Description

bool array_key_exists ( mixed $key, array $search )

array_key_exists() returns TRUE if the given key is set in the array. key can be any value possible for an array index. array_key_exists() also works on objects.

Parameters

key

            Value to check.

search

            An array with keys to check.

Return Values

Returns TRUE on success or FALSE on failure.

Examples array_key_exists() example

<?php
$search_array = array('first' => 1, 'second' => 4);
if (array_key_exists('first', $search_array)) {
echo "The 'first' element is in the array";
}
?>

Example  array_key_exists() vs isset()

isset() does not return TRUE for array keys that correspond to a NULL value, while array_key_exists() does.

null, 'second' => 4); // returns false isset($search_array['first']); // returns true array_key_exists('first', $search_array); ?>