json_decode：array_reduce停止工作

Question

<?php 
$json = "http://pastebin.com/raw.php?i=e1Sw66C3"; 
$data = json_decode(file_get_contents($json), true); 

$data = $data['recenttracks']; 
$tracks=$data['track']; 

foreach ($tracks as $track) { 
    $artist = $track['artist']['#text']; 
    $title = $track['name']; 
    $url = $track['url']; 
    $image = array_reduce($track['image'], function ($image, array $i) { return $image ?: ($i['size'] == 'large' ? $i['#text'] : null); }); 
echo '<li><a rel="external nofollow" href="'.htmlentities($url, ENT_QUOTES, "UTF-8").'" title="', $title, '">', $artist, ' - ', $title, '</a></li>'; } 
echo ($image); 
?> 

這段代碼一直工作。現在我不知道爲什麼BOOM echo ($image);什麼都不輸出。 我無法弄清楚那個函數有什麼問題。代碼的其餘部分工作正常（其他信息從輸入中獲取）。您可以通過訪問file_get_contents中的鏈接查看輸入內容。

Answer 1

正如我在評論中寫的，以前你的代碼只是工作，因爲元素size = 'large'是最後一個，否則變量$image在每個循環被覆蓋。你需要的是這樣的

$json = "http://pastebin.com/raw.php?i=e1Sw66C3"; 
$data = json_decode(file_get_contents($json), true); 

$data = $data['recenttracks']; 
$tracks=$data['track']; 
$images = array(); 

foreach ($tracks as $track) { 
    $artist = $track['artist']['#text']; 
    $title = $track['name']; 
    $url = $track['url']; 
    if (isset($track['image']) && is_array($track['image'])) 
     foreach($track['image'] as $image) 
      if (isset($image['size']) && $image['size'] == 'large' && 
       isset($image['#text']) && !empty($image['#text'])) 
      $images[] = $image['#text']; 

    echo '<li><a rel="external nofollow" href="' . 
      htmlentities($url, ENT_QUOTES, "UTF-8") . '" title="', $title, '">', 
      $artist, ' - ', $title, '</a></li>'; 
} 
echo join("\n", $images);