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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); ?>