php查找数组元素各种方法总结

<?php

$searchValue = (int)$_GET['key'];

function search(array $array, $value)
{
$max = count($array)-1;
$min = 0;
$isAscSort = $array[$min] < $array[$max];

while (TRUE) {
$sum = $min+$max;
$midKey = (int)($sum%2 == 1 ? ceil($sum/2) : $sum/2);

if ($max < $min) {
return -1;
} else if ($value == $array[$midKey]) {
return 1;
} else if ($value > $array[$midKey]) {
$isAscSort ? $min = $midKey+1 : $max = $midKey-1;
} else if ($value < $array[$midKey]) {
$isAscSort ? $max = $midKey-1 : $min = $midKey+1;
}
}
}

$array = array(
'4', '5', '7', '8', '9', '10', '11', '12'
);
// 正序
echo search($array, $searchValue);

// 逆序
rsort($array);
echo search($array, $searchValue);

<?php
     #随机选择第i小的数字，用随机快排实现
    
     #交换元素
     function swap(&$arr, $i, $j) {
         $temp = $arr[$i];
         $arr[$i] = $arr[$j];
         $arr[$j] = $temp;
     }
 
     #随机划分
     function randomized_partition(&$arr, $begin, $end) {
         $rand_inx = rand($begin, $end);
         swap($arr, $begin, $rand_inx);
         return partition($arr, $begin, $end);
     }
 
     #划分
     function partition(&$arr, $begin, $end) {
         #以第一个元素作为中枢元素
         $pivot = $begin;
         $low = $begin;
         $high = $end;
 
         while ($low < $high) {
             while ($low < $high && $arr[$low] <= $arr[$pivot]) {
                 $low++;
             }
 
             while ($low < $high && $arr[$high] >= $arr[$pivot]) {
                 $high--;
             }
 
             swap($arr, $low, $high);
         }
 
         #交换中枢元素
         if ($arr[$pivot] < $arr[$low]) {
             $low--;
         }
         swap($arr, $pivot, $low);
         return $low;
     }
 
     #快速排序，此处没用到
     function quick_sort(&$arr, $begin, $end) {
         $q = randomized_partition($arr, $begin, $end);
         if ($q > $begin) {
             quick_sort($arr, $begin, $q - 1);
         }
         if ($q < $end) {
             quick_sort($arr, $q + 1, $end);
         }
     }
 
     #选取第i小的数
     function randomized_select(&$arr, $begin, $end, $i) {
         if ($begin == $end) {
             return $arr[$begin];
         }
 
         $q = randomized_partition($arr, $begin, $end);
         $k = $q - $begin + 1; #k代表小于等于q的元素个数
 
         if ($k == $i) { #如果k=i,说明q就是第i小的元素坐标
             return $arr[$q];
         } else if ($i < $k) { #如果i<k，说明第i小的元素位于q的左边
             return randomized_select($arr, $begin, $q - 1, $i);
         } else { #第i小的元素位于q的右边,此时查找右边的第i-k小的元素
             return randomized_select($arr, $q + 1, $end, $i - $k);
         }
     }
 
     $arr = array(1, 5, 3, 7, 0, 0, 8, 4, 2, 9, 11);
     $t = randomized_select($arr, 0, count($arr) - 1, 8);
     print_r("The 8th minimum element: {$t}");
     echo "<br>";
     quick_sort($arr, 0, count($arr) - 1);
     print_r($arr);
 ?>

$str="ssdsf<a target='_blank' href='http://www.111cn.net/' >sdf</a>sdfss";
if(preg_match("/<a/s+href=[^>]*>|<//[^a]*a[^>]*>/i",$str))
{
echo "该字符串有超链接";
}
else
{
echo "该字符串没有超链接标记";
}
?>

<?php
echo preg_replace("/(?<=href=)([^>]*)(?=>)/i","#", "<a href='www.111cn.net'>你好，点这里看看</a><a href='www.111cn.net'>你好，点这里看看</a>");
?>

function match_links($document) {   

    preg_match_all("'<s*as.*?hrefs*=s*(["'])?(?(1)(.*?)\1|([^s>]+))[^>]*>?(.*?)</a>'isx",$document,$links);                       

    while(list($key,$val) = each($links[2])) {

        if(!empty($val))

            $match['link'][] = $val;

    }

    while(list($key,$val) = each($links[3])) {

        if(!empty($val))

            $match['link'][] = $val;

    }       

    while(list($key,$val) = each($links[4])) {

        if(!empty($val))

            $match['content'][] = $val;

    }

    while(list($key,$val) = each($links[0])) {

        if(!empty($val))

            $match['all'][] = $val;

    }               

    return $match;

}

(http[s]{0,1}|ftp)://[a-zA-Z0-9\.\-]+\.([a-zA-Z]{2,4})(:\d+)?(/[a-zA-Z0-9\.\-~!@#$%^&*+?:_/=<>]*)?

<?php
// $html        = the html on the page
// $current_url = the full url that the html came from (only needed for $repath)
// $repath      = converts ../ and / and // urls to full valid urls
function pageLinks($html, $current_url = "", $repath = false){
    preg_match_all("/<a.+?href=("|')(?!javascript:|#)(.+?)("|')/i", $html, $matches);
    $links = array();
    if(isset($matches[2])){
        $links = $matches[2];
    }
    if($repath && count($links) > 0 && strlen($current_url) > 0){
        $pathi      = pathinfo($current_url);
        $dir        = $pathi["dirname"];
        $base       = parse_url($current_url);
        $split_path = explode("/", $dir);
        $url        = "";
        foreach($links as $k => $link){
            if(preg_match("/^../", $link)){
                $total = substr_count($link, "../");
                for($i = 0; $i < $total; $i++){
                    array_pop($split_path);
                }
                $url = implode("/", $split_path) . "/" . str_replace("../", "", $link);
            }elseif(preg_match("/^///", $link)){
                $url = $base["scheme"] . ":" . $link;
            }elseif(preg_match("/^/|^.//", $link)){
                $url = $base["scheme"] . "://" . $base["host"] . $link;
            }elseif(preg_match("/^[a-zA-Z0-9]/", $link)){
                if(preg_match("/^http/", $link)){
                    $url = $link;
                }else{
                    $url       = $dir . "/" . $link;
                }
            }
            $links[$k] = $url;
        }
    }
    return $links;
}
header("content-type: text/plain");
$url = "http://www.111cn.net";
$html = file_get_contents($url);
// Gets links from the page:
print_r(pageLinks($html));

// Gets links from the page and formats them to a full valid url:
print_r(pageLinks($html, $url, true));