场景:各种文件的大小以字节的形式存储在数据库中。把这个大小信息格式化为千字节、兆字节和千兆字节的最好方法是什么?例如,我有一个MP3, Ubuntu显示为“5.2 MB(5445632字节)”。我如何在网页上显示这为“5.2 MB”,并有文件小于1兆字节显示为KB和文件1gb及以上显示为GB?


当前回答

伪代码:

$base = log($size) / log(1024);
$suffix = array("", "k", "M", "G", "T")[floor($base)];
return pow(1024, $base - floor($base)) . $suffix;

其他回答

function convertToReadableSize($size)
{
  $base = log($size) / log(1024);
  $suffix = array("B", "KB", "MB", "GB", "TB");
  $f_base = floor($base);
  return round(pow(1024, $base - floor($base)), 1) . $suffix[$f_base];
}

只需要调用函数

echo convertToReadableSize(1024); // Outputs '1KB'
echo convertToReadableSize(1024 * 1024); // Outputs '1MB'

伪代码:

$base = log($size) / log(1024);
$suffix = array("", "k", "M", "G", "T")[floor($base)];
return pow(1024, $base - floor($base)) . $suffix;

下面是Drupal format_size函数的简化实现:

/**
 * Generates a string representation for the given byte count.
 *
 * @param $size
 *   A size in bytes.
 *
 * @return
 *   A string representation of the size.
 */
function format_size($size) {
  if ($size < 1024) {
    return $size . ' B';
  }
  else {
    $size = $size / 1024;
    $units = ['KB', 'MB', 'GB', 'TB'];
    foreach ($units as $unit) {
      if (round($size, 2) >= 1024) {
        $size = $size / 1024;
      }
      else {
        break;
      }
    }
    return round($size, 2) . ' ' . $unit;
  }
}

简单的函数

function formatBytes($size, $precision = 0){
    $unit = ['Byte','KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'];

    for($i = 0; $size >= 1024 && $i < count($unit)-1; $i++){
        $size /= 1024;
    }

    return round($size, $precision).' '.$unit[$i];
}

echo formatBytes('1876144', 2);
//returns 1.79 MiB
function formatBytes($bytes, $precision = 2) { 
    $units = array('B', 'KB', 'MB', 'GB', 'TB'); 

    $bytes = max($bytes, 0); 
    $pow = floor(($bytes ? log($bytes) : 0) / log(1024)); 
    $pow = min($pow, count($units) - 1); 

    // Uncomment one of the following alternatives
    // $bytes /= pow(1024, $pow);
    // $bytes /= (1 << (10 * $pow)); 

    return round($bytes, $precision) . ' ' . $units[$pow]; 
} 

(摘自php.net,有很多其他的例子,但我最喜欢这个:-)