PHP按照一定的標準排序對象數組？

Question

我有這樣的事情：

$i = 0; 

foreach($tracks['results'] as $track){ 
    $trackName[$i] = $track['name']; 
    $trackPlaycount[$track['name']] = $track['playcount']; 
    $trackPercent[$track['name']] = $track['percent']; 
    $i++; 
} 

$this->trackName = $trackName; 
$this->trackPlaycount = $trackPlaycount; 
$this->trackPercent = $trackPercent; 

我怎麼可能通過playcount這些對象進行排序？從我目前閱讀的內容來看，我明白我應該創建一個比較函數，然後使它與usort（）一起工作，對吧？但我不太清楚如何實現這一目標？

謝謝

編輯：好了，現在我有這樣的：

public function firstmethod(){ 
    // there are some more parameters here of course 
    // but they worked before, not important for the problem 
    $i = 0; 
    foreach($tracks['results'] as $track){ 
     $trackName[$i] = $track['name']; 
     $trackPlaycount[$track['name']] = $track['playcount']; 
     $trackPercent[$track['name']] = $track['percent']; 
     // this part is new 
     $tracksArray[$i] = array(
      'name' => $trackName[$i], 
      'playcount' => $trackPlaycount[$track['name']], 
      'percentage' => $trackPercent[$track['name']] 
     ); 
     $i++; 
    } 

    usort($tracksArray, array($this, 'sortByCount')); 

    $i = 0; 
    // this is to put the new sorted array into the old variables? 
    foreach($tracksArray as $temp){ 
     $trackName[$i] = $temp['name']; 
     $trackPlaycount[$trackName[$i]] = $temp['playcount']; 
     $trackPercent[$trackName[$i]] = $temp['percentage']; 
     $i++; 
    } 

    $this->trackName = $trackName; 
    $this->trackPlaycount = $trackPlaycount; 
    $this->trackPercent = $trackPercent; 
} 


public function sortByCount($a, $b){ 
    if($a["playcount"] == $b["playcount"]) { 
     return 0; 
    } 
    return ($a["playcount"] < $b["playcount"]) ? -1 : 1; 
} 

This now works ... 謝謝大家

Answer 1

例如：

在自定義功能，你只需訪問你關心這樣的數組鍵：

?php 
$people = array(
    array('id' => 1, 'name' => 'John', 'age' => 12), 
    array('id' => 2, 'name' => 'Mary', 'age' => 14), 
    array('id' => 3, 'name' => 'Aaaaaadam', 'age' => 15) 
); 

usort($people, "sortByName"); 
var_dump($people); 
usort($people, "sortByAge"); 
var_dump($people); 

function sortByName($a, $b) { 
    return strcmp($a["name"], $b["name"]); 
} 

function sortByAge($a, $b) { // or playcount or whatever 
    if($a["age"] == $b["age"]) { 
     return 0; 
    } 
    return ($a["age"] < $b["age"]) ? -1 : 1; 
} 

打印數組排序（僅粘貼一個，所以它沒有得到長期，其他輸出按年齡相應排序）

array(3) { 
    [0]=> 
    array(3) { 
    ["id"]=> 
    int(3) 
    ["name"]=> 
    string(9) "Aaaaaadam" 
    ["age"]=> 
    int(15) 
    } 
    [1]=> 
    array(3) { 
    ["id"]=> 
    int(1) 
    ["name"]=> 
    string(4) "John" 
    ["age"]=> 
    int(12) 
    } 
    [2]=> 
    array(3) { 
    ["id"]=> 
    int(2) 
    ["name"]=> 
    string(4) "Mary" 
    ["age"]=> 
    int(14) 
    } 
} 

Answer 2

您也可以使用SplMaxHeap這個。借用@edorian's $people array，你可以做

class SortByAge extends SplMaxHeap 
{ 
    function compare($a, $b) 
    { 
     return $a['age'] - $b['age']; 
    } 
} 

$sort = new SortByAge; 
foreach($people as $person) { 
    $sort->insert($person); 
} 

print_r(iterator_to_array($sort)); 

這應該perform somewhat better比usort。