PHP: 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

Example #1 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";

}

?>

Note: The name of this function is key_exists() in PHP 4.0.6.

Example #2 array_key_exists() vs isset()

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


<?php

$search_array = array('first' => null, 'second' => 4);



// returns false

isset($search_array['first']);



// returns true

array_key_exists('first', $search_array);

?>

array_key_exists

Description

Parameters

Return Values

Examples

See Also