比較字符串，使用較短的字符串

Question

我是一個剛開始的程序員，試圖製作一個簡單的應用程序，只需要一個網站並返回值。

我試圖做一些我認爲很簡單的事情，但經過搜索和嘗試後，已經放棄了只是問。

用我的刮板，我返回三個變量：$ TITLE1，$標題2，並$ TITLE3。所有的$標題都來自我嘗試查找文章名稱的不同方法。理想情況下，我只需要尋找一個並完成，但有些網站存儲數據不同（有些通過元標記，隱藏的div，元素等）。

我需要一種方法來做到以下僞代碼：

if $title1, $title2, $title3 != null { // don't count a string if it is null 

    $title1_stringlength = string_length($title1) //find string length of the $titles 
    $title2_stringlength = string_length($title2) 
    $title3_stringlength = string_length($title3) 

    $realtitle = $lowestvalueofstringlength; // $realtitle gets whichever $title is shortest in length, not counting any null $title's 

} 

這就是爲什麼我需要做這樣一個例子：

echo $title1; //echoes "Exercise Daily" 
echo $title2; //echoes "null" 
echo $title3; //echoes "Exercise Daily - And More advice on SaveTheTwinkie.org" 
$realtitle = $title1;//should be $title1 because it was shortest that wasn't null 

//or a different example from another site 

echo $title1; //echoes "Wow look at this Article Title!" 
echo $title2; //echoes "null" 
echo $title3; //echoes "Wow look at this Article Title! - from StupidArticles.tv" 
$realtitle = $title1;//should be $title1 because it was shortest that wasn't null 

所以我的代碼將在最短的$標題在字符串長度（不是空值）中，並將值賦給$ realtitle。

感謝您的幫助！如果你需要更多的細節，請問！

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編輯

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我的繼承人完整的代碼：它的工作原理，直到在$稱號的是一個 「」，那麼$ realtitle變爲 「」 以及

<?php 

$sites_html = file_get_contents($url); 

$html = new DOMDocument(); 
@$html->loadHTML($sites_html); 
$title1 = null; //reset 
$title2 = null; //reset 
$title3 = null; //reset 

//Get all meta tags and loop through them. 
foreach($html->getElementsByTagName('meta') as $meta) { 
    if($meta->getAttribute('property')=='og:title'){ 
     //Assign the value from content attribute to $title1 
     $title1 = $meta->getAttribute('content'); 
    } 
} 
foreach($html->getElementsByTagName('h1') as $div) { 
    if($div->getAttribute('itemprop')=='name'){ 
     $title2 = $div->nodeValue; 
    } 
} 
foreach($html->getElementsByTagName('h1') as $div) { 
    if($div->getAttribute('class')=='fn'){ 
     $title3 = $div->nodeValue; 
    } 
} 

$realtitle = array_reduce(array($title2, $title1, $title3), function($a, $b) { 
    return strlen($a) && $a != 'null' && strlen($a) < strlen($b) ? $a : $b; 
}, null); 

    echo 'metaogtitle: '.$title1 . '<br/><br/><br/><br/><br/>'; 
    echo 'name: '.$title2. '<br/><br/><br/><br/><br/>'; 
    echo 'name2: '.$title3. '<br/><br/><br/><br/><br/>'; 
    echo 'realtitle: '.$realtitle. '<br/><br/><br/><br/><br/>'; 
?> 

Answer 1

// Filter invalid values 
$titles = array_filter($titles, function($title) { return $title && $title != 'null'; }); 
// Just sort :) 
usort ($titles, function ($left, $right) { return strlen($left) - strlen($right); }); 
echo $titles[0]; 

Answer 2

這一個應該工作：

function real_title($titles) { 
    /* Gets array of titles. 
     Return the shortest that isn't null. 
    */ 

    $min_length = strlen($titles[0]); 
    $real_title = $titles[0]; 

    foreach ($titles as $single_title) { 
     $title_length = strlen($single_title); 
     if (($title_length < $min_length) && ($title_length > 0)) { 
       $min_length = $title_length; 
       $real_title = $single_title; 
     } 
    } 

    return $real_title; 
} 

Answer 3

這裏是一個具有無限數量的字符串工作的變種：

$shortest = NULL; 

$shortestReduce = function ($string) use (&$shortest) { 

    if (($string === "null") || !($len = strlen($string))) { 
     return $shortest; 
    } 

    if (!isset($shortest) || $len < strlen($shortest)) { 
     $shortest = $string; 
    } 

    return $shortest; 
}; 

$shortestReduce($string1); 
$shortestReduce($string2); 
$shortestReduce($string3); 
# ... 

echo $shortest; # "Exercise Daily" 

這降低，可以應用在多個值產生一個結果，這裏不是"null"最短的字符串相同的功能。