php - 多次元連想配列の順序付け

Question

この配列を価格で注文し、キーを変更せずに保持したいと考えています。

これが私が取り組んできたものです。

<?php 

$a = array(
        1=>array('price'=>9.25,'timestamp_added'=>1301945848,'name'=>'pencils'),
        4=>array('price'=>19.15,'timestamp_added'=>1299267448,'name'=>'crayon box'),
        15=>array('price'=>4.25,'timestamp_added'=>1299785848,'name'=>'markers'),
        2=> array('price'=>4.28,'timestamp_added'=>1299785848,'name'=>'eraser'),
        44=>array('price'=>13.99,'timestamp_added'=>1299872248,'name'=>'trapper'),
        32=>array('price'=>9.25,'timestamp_added'=>1299872248,'name'=>'notebook'),
        14=>array('price'=>13.99,'timestamp_added'=>1301945848,'name'=>'sharpener'),
        5=>array('price'=>15.01,'timestamp_added'=>1299872248,'name'=>'calculator')
);

function printList( $a ){
    echo "<br />";
    foreach ($a as $key => $value){
        echo "<br /> Product ID $key Price: " . $value['price'] . " Timestamp: " . $value['timestamp_added'] . " Name: " . $value['name'];
    }

}

printList( $a );
$price = array();
foreach ($a as $key => $row)
{
    $price[$key] = $row['price'];
}
array_multisort($price, SORT_ASC, $a);
printList( $a );
?>

出力：

Product ID 1 Price: 9.25 Timestamp: 1301945848 Name: pencils
Product ID 4 Price: 19.15 Timestamp: 1299267448 Name: crayon box
Product ID 15 Price: 4.25 Timestamp: 1299785848 Name: markers
Product ID 2 Price: 4.28 Timestamp: 1299785848 Name: eraser
Product ID 44 Price: 13.99 Timestamp: 1299872248 Name: trapper
Product ID 32 Price: 9.25 Timestamp: 1299872248 Name: notebook
Product ID 14 Price: 13.99 Timestamp: 1301945848 Name: sharpener
Product ID 5 Price: 15.01 Timestamp: 1299872248 Name: calculator

Product ID 0 Price: 4.25 Timestamp: 1299785848 Name: markers
Product ID 1 Price: 4.28 Timestamp: 1299785848 Name: eraser
Product ID 2 Price: 9.25 Timestamp: 1299872248 Name: notebook
Product ID 3 Price: 9.25 Timestamp: 1301945848 Name: pencils
Product ID 4 Price: 13.99 Timestamp: 1299872248 Name: trapper
Product ID 5 Price: 13.99 Timestamp: 1301945848 Name: sharpener
Product ID 6 Price: 15.01 Timestamp: 1299872248 Name: calculator
Product ID 7 Price: 19.15 Timestamp: 1299267448 Name: crayon box

配列をソートしますが、キーが変更されます。鍵のラベルを元の状態に保つにはどうすればよいですか?

Answer 1

uasort関数を使用できます

$a = array(
           1=>array('price'=>9.25,'timestamp_added'=>1301945848,'name'=>'pencils'),
           4=>array('price'=>19.15,'timestamp_added'=>1299267448,'name'=>'crayon box'),
           15=>array('price'=>4.25,'timestamp_added'=>1299785848,'name'=>'markers'),
           2=> array('price'=>4.28,'timestamp_added'=>1299785848,'name'=>'eraser'),
           44=>array('price'=>13.99,'timestamp_added'=>1299872248,'name'=>'trapper'),
           32=>array('price'=>9.25,'timestamp_added'=>1299872248,'name'=>'notebook'),
           14=>array('price'=>13.99,'timestamp_added'=>1301945848,'name'=>'sharpener'),
           5=>array('price'=>15.01,'timestamp_added'=>1299872248,'name'=>'calculator')
           );

function printList( $a ){
  echo "<br />";
  foreach ($a as $key => $value){
    echo "<br /> Product ID $key Price: " . $value['price'] . " Timestamp: " . $value['timestamp_added'] . " Name: " . $value['name'];
  }

}

printList( $a );

function sbyprice($a, $b)
{
   return ($a['price'] >= $b['price']) ? 1 : 0;
}

uasort($a , "sbyprice");
printList( $a );
?>

出力:

Product ID 1 Price: 9.25 Timestamp: 1301945848 Name: pencils
Product ID 4 Price: 19.15 Timestamp: 1299267448 Name: crayon box
Product ID 15 Price: 4.25 Timestamp: 1299785848 Name: markers
Product ID 2 Price: 4.28 Timestamp: 1299785848 Name: eraser
Product ID 44 Price: 13.99 Timestamp: 1299872248 Name: trapper
Product ID 32 Price: 9.25 Timestamp: 1299872248 Name: notebook
Product ID 14 Price: 13.99 Timestamp: 1301945848 Name: sharpener
Product ID 5 Price: 15.01 Timestamp: 1299872248 Name: calculator

Product ID 15 Price: 4.25 Timestamp: 1299785848 Name: markers
Product ID 2 Price: 4.28 Timestamp: 1299785848 Name: eraser
Product ID 32 Price: 9.25 Timestamp: 1299872248 Name: notebook
Product ID 1 Price: 9.25 Timestamp: 1301945848 Name: pencils
Product ID 44 Price: 13.99 Timestamp: 1299872248 Name: trapper
Product ID 14 Price: 13.99 Timestamp: 1301945848 Name: sharpener
Product ID 5 Price: 15.01 Timestamp: 1299872248 Name: calculator
Product ID 4 Price: 19.15 Timestamp: 1299267448 Name: crayon box

Answer 2

uasortはあなたのためのものです

例えば：

<?php
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a<$b)?-1:1;
}

$arr=array("a"=>4,"b"=>2,"c"=>8,d=>"6");
uasort($arr,"my_sort");
?> 

Answer 3

他のものと同じですが、インライン関数を使用しています。これはより良いかもしれません:

uasort ( $array , function($a, $b) {
  return $a['price'] >= $b['price'] ? 1 : 0 ;
});

Answer 4

usortはあなたの問題を解決します。このリンクを参照してください。