php 生成N个不重复的随机数实例详解

/** 

 * 生成一定数量的不重复随机数 

 * @param int $min ,$max指定随机数的范围 

 * @param int $max 

 * @param int $num 指定生成数量 

 * @return array 

 */

function unique_rand($min, $max, $num) { 

    $count = 0; 

    $return = array(); 

    while ($count < $num) { 

        $return[] = mt_rand($min, $max); 

        $return = array_flip(array_flip($return)); 

        $count = count($return); 

    } 

    shuffle($return); 

    return $return; 

}

<?php 

// 创建一对cURL资源 

$ch1 = curl_init(); 

$ch2 = curl_init(); 

// 设置URL和相应的选项 

curl_setopt($ch1, CURLOPT_URL, "http://lxr.php.net/"); 

curl_setopt($ch1, CURLOPT_HEADER, 0); 

curl_setopt($ch2, CURLOPT_URL, "http://www.php.net/"); 

curl_setopt($ch2, CURLOPT_HEADER, 0); 

// 创建批处理cURL句柄 

$mh = curl_multi_init(); 

// 增加2个句柄 

curl_multi_add_handle($mh,$ch1); 

curl_multi_add_handle($mh,$ch2); 

$active = null; 

// 执行批处理句柄 

do { 

    $mrc = curl_multi_exec($mh, $active); 

} while ($mrc == CURLM_CALL_MULTI_PERFORM); 

while ($active && $mrc == CURLM_OK) { 

    if (curl_multi_select($mh) != -1) { 

        do { 

            $mrc = curl_multi_exec($mh, $active); 

        } while ($mrc == CURLM_CALL_MULTI_PERFORM); 

    } 

} 

// 关闭全部句柄 

curl_multi_remove_handle($mh, $ch1); 

curl_multi_remove_handle($mh, $ch2); 

curl_multi_close($mh); 

?>

do { 

                        $mrc = curl_multi_exec($mh,$active); 

                 } while ($mrc == CURLM_CALL_MULTI_PERFORM); 

                while ($active and $mrc == CURLM_OK) { 

                        if (curl_multi_select($mh) != -1) { 

                                do { 

                                        $mrc = curl_multi_exec($mh, $active); 

                                 } while ($mrc == CURLM_CALL_MULTI_PERFORM); 

                         } 

                 }

$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' => 3 ) ,
'2' => array ( 'date' => '2011-08-20', 'num' => 5 ) ,
'3' => array ( 'date' => '2011-08-17', 'num' => 10 )
 )  ;用到的函数：

/**
 * @package     二维数组排序
 * @version     $Id: FunctionsMain.inc.php,v 1.32 2011/09/24 11:38:37 wwccss Exp $
 *
 *
 * 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;
}

<?php
 
 $arr = '';
 
 echo '二维数组如下：'.'<br / >';
 for($i=0; $i<=5; $i++)
 {
  $arr[$i]['val'] = mt_rand(1, 100);
  $arr[$i]['num'] = mt_rand(1, 100);
 }
 
 echo '<pre>';
 print_r($arr);
 echo '</pre>';
 
 echo '从二维数组中抽出键为val，单独成另一个数组：'.'<br / >';
 foreach ($arr as $key => $row)
 {
     $vals[$key] = $row['val'];
        $nums[$key] = $row['num'];
 }
 
 echo '<pre>';
 print_r($vals);
 echo '</pre>';
 
 echo '对其进行排序：'.'<br / >';
 array_multisort($vals, SORT_ASC, $arr);
 
 echo '<pre>';
 print_r($vals);
 echo '</pre>';
 
?>