在while循环中使用regex函数

Question

我有一个从特定网站获取特定链接的函数，它可以工作，但是当我尝试在while循环中使用此函数时，问题就开始了。 当我尝试这样做时，由于某种原因，链接长度开始堆积。

function getLinks($link) {

$link1 = $link;
$content = file_get_contents($link1);

$content = str_replace("<", "", $content);
$content = str_replace(">", "", $content);

preg_match("~previous page.+?next page~i", $content, $match);
preg_match("~\"(/.+?)\"~i", $match[0], $match);
$link2 = "https://en.wiktionary.org".$match[1];

echo $link1."<br>";
echo $link2."<br>";

return $link2;

}


$firstLink = getLinks("https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=AUTOPILOT%0Aautopilot#mw-pages");

结果firstLink = getLinks（）：

https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=AUTOPILOT%0Aautopilot#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=BAGSIE%0Abagsie#mw-pages

^ ---看到这种情况如何运作？ 然后，当我将其放入while循环中时：

$count = 0; 
while ($count < 5) {

$count++;
$firstLink = getLinks($firstLink);

}

结果完全混乱了，链接开始相互堆叠，就像这样：

https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=AUTOPILOT%0Aautopilot#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=BAGSIE%0Abagsie#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=BAGSIE%0Abagsie#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bpagefrom=BAGSIE%0Abagsie&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bpagefrom=BAGSIE%0Abagsie&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bamp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bamp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bamp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bamp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages
https://en.wiktionary.org/w/index.php?title=Category:English_verbs&amp%3Bamp%3Bamp%3Bamp%3Bamp%3Bpagefrom=BAGSIE%0Abagsie&amp%3Bamp%3Bamp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bamp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bamp%3Bpagefrom=ACETIFY%0Aacetify&amp%3Bpagefrom=ACETIFY%0Aacetify&pagefrom=ACETIFY%0Aacetify#mw-pages

这让我发疯，所以如果有人知道我做错了，请告诉我。 谢谢。

while循环中的常规功能：

function addOne($num) {

echo $num."<br>";   
$num++;
return $num;    

}

$num = 0;
$count = 0;
while ($count < 5) {

$count++;
$num = addOne($num);    

}

^ ---效果很好

Answer 1

您的问题出在HTML实体上。 我重新编写了该函数，以解决该问题，重复的URL并提高效率。 您可以使用depth参数来调用它，在您的情况下，这将是您的while最大值。

function getLinks($linkd, $depth, $checked=array()) {

if(!is_array($linkd)) $linkd=array($linkd);
    foreach($linkd as $link)
    {
        if(isset($checked[$link])) continue;
        $link1 = $link;
        $content = file_get_contents($link1);

        $content = str_replace("<", "", $content);
        $content = str_replace(">", "", $content);

        preg_match("~previous page.+?next page~i", $content, $match);
        preg_match("~\"(/.+?)\"~i", $match[0], $match);
        $link2 = "https://en.wiktionary.org".$match[1];

        echo $link1."<br>";
        echo $link2."<br>";

        $checked[$link] = true;

        if($depth>0)
        {
            $depth--;
            return getLinks(html_entity_decode($link2), $depth, $checked);
        }
        else
        {
            return $link2;
        }

    }
}


$firstLink = "https://en.wiktionary.org/w/index.php?title=Category:English_verbs&pagefrom=AUTOPILOT%0Aautopilot#mw-pages";

$firstLink = getLinks($firstLink, 5);