<?php

$a = array("a" => "apple", "b" => "banana");

$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");

echo "a: </br> ";

print_r($a);

echo " </br> b:   </br>";

print_r($b);

$c = $a + $b;

echo " </br>Union of \$a and \$b: </br>";

var_dump($c);

$c = $b + $a;

echo " </br>Union of \$b and \$a:  </br>";

var_dump($c);

$a += $b;

echo " </br>Union of \$a += \$b:  </br>";

var_dump($a);

?>