Answers for "php array contains by valyue key"

php key in array exists

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

// returns false
isset($search_array['first']);

// returns true
array_key_exists('first', $search_array);
?>

php array has value

$myArr = [38, 18, 10, 7, "15"];

echo in_array(10, $myArr); // TRUE
echo in_array(19, $myArr); // TRUE

// Without strict check
echo in_array("18", $myArr); // TRUE
// With strict check
echo in_array("18", $myArr, true); // FALSE