<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');
echo "Using array_search() function: <br>";
$key = array_search('green', $array); // $key = 2;
echo "Value green is at the location : ". $key."<br>";
echo "------------------------------------<br>";
echo "Using in_array() function: <br>";
$a = array('1.10', 12.4, 1.13);

if (in_array('12.4', $a, true)) {
    echo "'12.4' found with strict check <br>";
}

if (in_array(1.13, $a, true)) {
    echo "1.13 found with strict check <br>";
}
echo "------------------------------------<br>";
echo "Using array_key_exists() function : <br>";
$search_array = array('first' => 1, 'second' => 4);
if (array_key_exists('first', $search_array)) 
    echo "The 'first' element is in the array <br>";
echo "------------------------------------<br>";
echo "Using array_values() function : <br> ";
$array = array("size" => "XL", "color" => "gold");
print_r(array_values($array));
echo "<br>";
echo "Using array_keys() function : <br> ";
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));
echo "<br>";

$array = array("color" => array("blue", "red", "green"),
    "size"  => array("small", "medium", "large"));
print_r(array_keys($array));
?>