php二维数组排序详解

$arr=array (
'1' => array ( 'date' => '2011-08-18','num' => 5 ),
'2' => array ( 'date' => '2011-08-20','num' => 3 ),
'3' => array ( 'date' => '2011-08-17','num' => 10 )
) ; $result = sysSortArray($arr,'num');这样运行之后的效果为：
$arr=array (
'1' => array ( 'date' => '2011-08-18','num' => 10 )
) ;用到的函数：
/**
* Sort an two-dimension array by some level two items use array_multisort() function.
*
* sysSortArray($Array,"Key1","SORT_ASC","SORT_RETULAR","Key2";……)
* @author lamp100
* @param array $ArrayData the array to sort.
* @param string $KeyName1 the first item to sort by.
* @param string $SortOrder1 the order to sort by("SORT_ASC"|"SORT_DESC")
* @param string $SortType1 the sort type("SORT_REGULAR"|"SORT_NUMERIC"|"SORT_STRING")
* @return array sorted array.
*/
function sysSortArray($ArrayData,$KeyName1,$SortOrder1 = "SORT_ASC",$SortType1 = "SORT_REGULAR")
{
if(!is_array($ArrayData))
{
return $ArrayData;
}
// Get args number.
$ArgCount = func_num_args();
// Get keys to sort by and put them to SortRule array.
for($I = 1;$I < $ArgCount;$I ++)
{
$Arg = func_get_arg($I);
if(!eregi("SORT",$Arg))
{
$KeyNameList[] = $Arg;
$SortRule[] = '$'.$Arg;
}
else
{
$SortRule[] = $Arg;
}
}
// Get the values according to the keys and put them to array.
foreach($ArrayData AS $Key => $Info)
{
foreach($KeyNameList AS $KeyName)
{
${$KeyName}[$Key] = $Info[$KeyName];
}
}
// Create the eval string and eval it.
$EvalString = 'array_multisort('.join(",",$SortRule).',$ArrayData);';
eval ($EvalString);
return $ArrayData;
}

';
for($i=0; $i<=5; $i++)
{
$arr[$i]['val'] = mt_rand(1,100);
$arr[$i]['num'] = mt_rand(1,100);
}echo '

';
print_r($arr);
echo '

';echo '从二维数组中抽出键为val，单独成另一个数组：'.'
';
foreach ($arr as $key => $row)
{
$vals[$key] = $row['val'];
$nums[$key] = $row['num'];
}echo '

';
print_r($vals);
echo '

';echo '对其进行排序：'.'
';
array_multisort($vals,SORT_ASC,$arr);echo '

';
print_r($vals);
echo '

';?>