PHP array_multisort() 函数的深入解析

$guys = Array
(
    [0] => Array
        (
 [name] => jake
 [score] => 80
 [grade] => A
        )
    [1] => Array
        (
 [name] => jin
 [score] => 70
 [grade] => A
        )
    [2] => Array
        (
 [name] => john
 [score] => 80
 [grade] => A
        )
    [3] => Array
        (
 [name] => ben
 [score] => 20
 [grade] => B
        )
)

/
根据指定的键对数组排序

用法
@code php
$rows = array(
array('id' => 1, 'value' => '1-1', 'parent' => 1),
array('id' => 2, 'value' => '2-1', 'parent' => 1),
array('id' => 3, 'value' => '3-1', 'parent' => 1),
array('id' => 4, 'value' => '4-1', 'parent' => 2),
array('id' => 5, 'value' => '5-1', 'parent' => 2),
array('id' => 6, 'value' => '6-1', 'parent' => 3),
);

$rows = Helper_Array::sortByCol($rows, 'id', SORT_DESC);
dump($rows);
// 输出结果为
// array(
//         array('id' => 6, 'value' => '6-1', 'parent' => 3),
//         array('id' => 5, 'value' => '5-1', 'parent' => 2),
//         array('id' => 4, 'value' => '4-1', 'parent' => 2),
//         array('id' => 3, 'value' => '3-1', 'parent' => 1),
//         array('id' => 2, 'value' => '2-1', 'parent' => 1),
//         array('id' => 1, 'value' => '1-1', 'parent' => 1),
// )
@endcode

@param array $array 要排序的数组
@param string $keyname 排序的键
@param int $dir 排序方向

@return array 排序后的数组
/
          static function sortByCol($array, $keyname, $dir = SORT_ASC)
          {
   return self::sortByMultiCols($array, array($keyname => $dir));
          }
          /
将一个二维数组按照多个列进行排序，类似 SQL 语句中的 ORDER BY

用法
@code php
$rows = Helper_Array::sortByMultiCols($rows, array(
'parent' => SORT_ASC,
'name' => SORT_DESC,
));
@endcode

@param array $rowset 要排序的数组
@param array $args 排序的键

@return array 排序后的数组
/
          static function sortByMultiCols($rowset, $args)
          {
   $sortArray = array();
   $sortRule = '';
   foreach ($args as $sortField => $sortDir)
   {
       foreach ($rowset as $offset => $row)
       {
$sortArray[$sortField][$offset] = $row[$sortField];
       }
       $sortRule .= '$sortArray[\'' . $sortField . '\'], ' . $sortDir . ', ';
   }
   if (empty($sortArray) || empty($sortRule)) { return $rowset; }
   eval('array_multisort(' . $sortRule . '$rowset);');
   return $rowset;
          }