php(二维数组中按条件排序的一个小问题)
//原数组
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 ) )
//方法一、
$ar = Array ( 1 => Array ( 'date' => '2011-08-18', 'num' => 5 ),
2 => Array ( 'date' => '2011-08-20', 'num' => 3 ),
3 => Array ( 'date' => '2011-08-17', 'num' => 10 )
);
function mysort($a, $b) {
$a = strtotime($a['date']);
$b = strtotime($b['date']);
if ($a == $b) return 0;
return ($a < $b) ? -1 : 1;
}
usort($ar, 'mysort');
print_r($ar);
//方法二、
$arr=array (
'1' => array ( 'date' => '2011-08-18', 'num' => 5 ) ,
'2' => array ( 'date' => '2011-08-20', 'num' => 3 ) ,
'3' => array ( 'date' => '2011-08-17', 'num' => 10 )
) ;
foreach($arr as $v){
$tmp[$v[date]]=$v;
}
ksort($tmp);
print_r(array_values($tmp));
