<?php
$fruits = array(
	'water_melon' => '500yen', 
	'mikan' => '100yen', 
	'kaki' => '150yen', 
	'strowberry' => '400yen',
);

$winterOrder = array();
$winterOrder[] = 'mikan';
$winterOrder[] = 'kaki';

$summerOrder = array();
$summerOrder[] = 'water_melon';
$summerOrder[] = 'strowberry';

function makeRanking($fruits, $orderLists)
{
	$ret = array();

	foreach ( $orderLists as $fruitName ) {

		if ( isset($fruits[$fruitName]) ) {
			$ret[$fruitName] = $fruits[$fruitName];
			unset($fruits[$fruitName]);
		}
	}

	foreach ( $fruits as $fruitName => $fruit ) {
		$ret[$fruitName] = $fruit;
	}

	return $ret;
}


echo "冬の果物お勧めランキング\n";
echo "冬はやっぱり、こたつでミカンです。\n";

print_r(makeRanking($fruits, $winterOrder));


echo "夏の果物お勧めランキング\n";
echo "夏はやっぱり、縁側でスイカです。\n";

print_r(makeRanking($fruits, $summerOrder));
?>

冬の果物お勧めランキング
冬はやっぱり、こたつでミカンです。
Array
(
    [mikan] => 100yen
    [kaki] => 150yen
    [water_melon] => 500yen
    [strowberry] => 400yen
)
夏の果物お勧めランキング
夏はやっぱり、縁側でスイカです。
Array
(
    [water_melon] => 500yen
    [strowberry] => 400yen
    [mikan] => 100yen
    [kaki] => 150yen
)