排序算法

冒泡排序

function bubbleSort($numbers) {
    $cnt = count($numbers);
    for ($i = 0; $i < $cnt; $i++) {
        for ($j = 0; $j < $cnt - $i - 1; $j++) {
            if ($numbers[$j] > $numbers[$j + 1]) {
                $temp = $numbers[$j];
                $numbers[$j] = $numbers[$j + 1];
                $numbers[$j + 1] = $temp;
            }
        }
    }
     return $numbers;
}
 
$num = array(20, 40, 60, 80, 30, 70, 90, 10, 50, 0);
bubbleSort($num);

快速排序

function quickSort(&$arr){
    if(count($arr)>1){
        $k=$arr[0];
        $x=array();
        $y=array();
        $_size=count($arr);
        for($i=1;$i<$_size;$i++){
            if($arr[$i]<=$k){
                $x[]=$arr[$i];
            }elseif($arr[$i]>$k){
                $y[]=$arr[$i];
            }
        }
        $x=quickSort($x);
        $y=quickSort($y);
        return array_merge($x,array($k),$y);
    }else{
        return$arr;
    }
}

排序函数（类似 sql 的多字段排序）

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;
}