正则表达式模式以去除括号（和内部的任何括号内）

Question

输入是一个Wikipedia页面的第一个段落。我想删除括号和括号之间的任何内容。

然而，有时（通常），HTML内容括号内本身含有一个或数个括号，一般在一个链路的href=""。

采取以下：

<p> 
    The <b>Sarcopterygii</b> or <b>lobe-finned fish</b> (from Greek σαρξ <i>sarx</i>, flesh, and πτερυξ <i>pteryx</i>, fin) – sometimes considered synonymous with <b>Crossopterygii</b> ("fringe-finned fish", from Greek κροσσός <i>krossos</i>, fringe) – constitute a <a href="/wiki/Clade" title="Clade">clade</a> (traditionally a <a href="/wiki/Class_(biology)" title="Class (biology)">class</a> or subclass) of the <a href="/wiki/Osteichthyes" title="Osteichthyes">bony fish</a>, though a strict <a href="/wiki/Cladistic" class="mw-redirect" title="Cladistic">cladistic</a> view includes the terrestrial <a href="/wiki/Vertebrate" title="Vertebrate">vertebrates</a>. 
</p> 

我想最终的结果是：

<p> 
    The <b>Sarcopterygii</b> or <b>lobe-finned fish</b> – sometimes considered synonymous with <b>Crossopterygii</b> – constitute a <a href="/wiki/Clade" title="Clade">clade</a> of the <a href="/wiki/Osteichthyes" title="Osteichthyes">bony fish</a>, though a strict <a href="/wiki/Cladistic" class="mw-redirect" title="Cladistic">cladistic</a> view includes the terrestrial <a href="/wiki/Vertebrate" title="Vertebrate">vertebrates</a>. 
</p> 

但是当我使用下面的preg_replace模式它不工作，成为它就会迷茫圆括号内的括号。

public function removeParentheses($content) { 

    $pattern = '@\(.*?\)@'; 
    $content = preg_replace($pattern, '', $content); 
    $content = str_replace(' .', '.', $content); 
    $content = str_replace(' ', ' ', $content); 
    return $content; 
} 

其次，我怎么能离开内部链接href=""和title=""括号？这些，如果不在文本括号内，则很重要。

Answer 1

可以代替所有的占位符的链接，然后删除所有括号，并在年底替换占位符回到其原始值。

这与preg_replace_callback()完成，传递一个事件计数器和更换阵列保持联系的轨道，然后使用自己的removeParentheses()摆脱括号，最后用str_replace()与array_keys()和array_values()让你回链接：

<?php 
$string = '<p> 
The <b>Sarcopterygii</b> or <b>lobe-finned fish</b> (from Greek σαρξ <i>sarx</i>, flesh, and πτερυξ <i>pteryx</i>, fin) – sometimes considered synonymous with <b>Crossopterygii</b> ("fringe-finned fish", from Greek κροσσός <i>krossos</i>, fringe) – constitute a <a href="/wiki/Clade" title="Clade">clade</a> (traditionally a <a href="/wiki/Class_(biology)" title="Class (biology)">class</a> or subclass) of the <a href="/wiki/Osteichthyes" title="Osteichthyes">bony fish</a>, though a strict <a href="/wiki/Cladistic" class="mw-redirect" title="Cladistic">cladistic</a> view includes the terrestrial <a href="/wiki/Vertebrate" title="Vertebrate">vertebrates</a>. 
</p>'; 
$occurrences = 0; 
$replacements = []; 
$replacedString = preg_replace_callback("/<a .*?>.*?<\/a>/i", function($el) use (&$occurrences, &$replacements) { 
    $replacements["|||".$occurrences] = $el[0]; // the ||| are just to avoid unwanted matches 
    return "|||".$occurrences++; 
}, $string); 
function removeParentheses($content) { 
    $pattern = '@\(.*?\)@'; 
    $content = preg_replace($pattern, '', $content); 
    $content = str_replace(' .', '.', $content); 
    $content = str_replace(' ', ' ', $content); 
    return $content; 
} 
$replacedString = removeParentheses($replacedString); 
$replacedString = str_replace(array_keys($replacements), array_values($replacements), $replacedString); // get your links back 
echo $replacedString; 

Demo

结果

然而

<p> 
The <b>Sarcopterygii</b> or <b>lobe-finned fish</b> – sometimes considered synonymous with <b>Crossopterygii</b> – constitute a <a href="/wiki/Clade" title="Clade">clade</a> of the <a href="/wiki/Osteichthyes" title="Osteichthyes">bony fish</a>, though a strict <a href="/wiki/Cladistic" class="mw-redirect" title="Cladistic">cladistic</a> view includes the terrestrial <a href="/wiki/Vertebrate" title="Vertebrate">vertebrates</a>. 
</p> 

这一点在我看来脆。正如别人在评论中告诉你的，你shouldn't parse HTML with regular expressions。 A lot可以改变，你可以得到意想不到的结果。这可能会让你朝正确的方向。

编辑关于圆括号内的圆括号，您可以使用递归模式。看看this great answer by Bart Kiers：

function removeParentheses($content) { 
    $pattern = '@\(([^()]|(?R))*\)@'; 
    $content = preg_replace($pattern, '', $content); 
    $content = str_replace(' .', '.', $content); 
    $content = str_replace(' ', ' ', $content); 
    return $content; 
} 

Demo