Question

我是一个初学程序员，试图创建一个简单的应用程序，只是抓取一个网站并返回值。

我正在尝试做一些我认为很简单的事情，但在搜索和尝试之后，已经放弃了，只是问。

使用我的刮刀，我返回三个变量： $ title1 ， $ title2 和 $ title3 。所有$ title都来自我试图找到文章名称的不同方法。理想情况下，我只需要查找一个并完成，但有些网站以不同方式存储数据（有些通过元标记，隐藏的div，元素等）。

我需要一种方法来执行以下伪代码：

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

}

以下是我需要执行此操作的示例：

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

所以我的代码会查找字符串长度最短的$ title（不是null）并将值赋给$ realtitle。

感谢您的帮助！如果您需要更多详细信息，请询问！

修改

继承我的完整代码：直到其中一个$ title为“”，然后$ realtitle变为“”

<?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

这是一个使用无限数量字符串的变体：

$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"

此reduce允许您对生成一个结果的多个值应用相同的函数，这里是不是"null"的最短字符串。

Answer 3

这个应该有效：

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;
}

比较字符串，使用较短的字符串

3 个答案: