PHP正則表達式匹配關鍵字之外HTML標籤<a>

Question

我一直試圖做一個正則表達式匹配和替換HTML的部分關鍵詞的出現：

1. 我想匹配keyword和<strong>keyword</strong>
2. 但<a href="someurl.html" target="_blank">keyword</a>和<a href="someur2.html">already linked keyword </a>應不匹配

我只是在一號線的匹配（和更換）的keyword感興趣。

我想要這個的原因是用<a href="dictionary.php?k=keyword">keyword</s>代替keyword，但只有在keyword它不在<a>標籤內。

任何幫助將不勝感激！

Answer 1

我能夠做到我想要的東西（不使用正則表達式）由：

• 解析我的字符串
• 刪除所有<a>標籤（將它們複製到一個臨時數組，並保持一個佔位符的每個字符在字符串上）
• str_replace新字符串爲了替換所有關鍵字
• 重新填充它原來的佔位符<a>個標籤

這是我使用的代碼，如果別人需要它：

$str = <<<STRA 
Moses supposes his toeses are roses, 
but <a href="original-moses1.html">Moses</a> supposes erroneously; 
for nobody's toeses are posies of roses, 
as Moses supposes his toeses to be. 
Ganda <span class="cenas"><a href="original-moses2.html" target="_blank">Moses</a></span>! 
STRA; 

$arr1 = str_split($str); 

$arr_links = array(); 
$phrase_holder = ''; 
$current_a = 0; 
$goto_arr_links = false; 
$close_a = false; 

foreach($arr1 as $k => $v) 
{ 
    if ($close_a == true) 
    { 
     if ($v == '>') { 
      $close_a = false; 
     } 
     continue; 
    } 

    if ($goto_arr_links == true) 
    { 
     $arr_links[$current_a] .= $v; 
    } 

    if ($v == '<' && $arr1[$k+1] == 'a') { /* <a */ 
     // keep collecting every char until </a> 
     $arr_links[$current_a] .= $v; 
     $goto_arr_links = true; 
    } elseif ($v == '<' && $arr1[$k+1] == '/' && $arr1[$k+2] == 'a' && $arr1[$k+3] == '>') { /* </a> */ 
     $arr_links[$current_a] .= "/a>"; 

     $goto_arr_links = false; 
     $close_a = true; 
     $phrase_holder .= "{%$current_a%}"; /* put a parameter holder on the phrase */ 
     $current_a++; 
    }  
    elseif ($goto_arr_links == false) { 
     $phrase_holder .= $v; 
    } 
} 

echo "Links Array:\n"; 
print_r($arr_links); 
echo "\n\n\nPhrase Holder:\n"; 
echo $phrase_holder; 
echo "\n\n\n(pre) Final Phrase (with my keyword replaced):\n"; 
$final_phrase = str_replace("Moses", "<a href=\"novo-mega-link.php\">Moses</a>", $phrase_holder); 
echo $final_phrase; 
echo "\n\n\nFinal Phrase:\n"; 
foreach($arr_links as $k => $v) 
{ 
    $final_phrase = str_replace("{%$k%}", $v, $final_phrase); 
} 
echo $final_phrase; 

輸出：

鏈接陣：

Array 
(
    [0] => <a href="original-moses1.html">Moses</a> 
    [1] => <a href="original-moses2.html" target="_blank">Moses</a> 
) 

短語持有人：

Moses supposes his toeses are roses, 
but {%0%} supposes erroneously; 
for nobody's toeses are posies of roses, 
as Moses supposes his toeses to be. 
Ganda <span class="cenas">{%1%}</span>! 

（預）最後一個短語（與我的關鍵字替換）：

<a href="novo-mega-link.php">Moses</a> supposes his toeses are roses, 
but {%0%} supposes erroneously; 
for nobody's toeses are posies of roses, 
as <a href="novo-mega-link.php">Moses</a> supposes his toeses to be. 
Ganda <span class="cenas">{%1%}</span>! 

最後一個短語：

<a href="novo-mega-link.php">Moses</a> supposes his toeses are roses, 
but <a href="original-moses1.html">Moses</a> supposes erroneously; 
for nobody's toeses are posies of roses, 
as <a href="novo-mega-link.php">Moses</a> supposes his toeses to be. 
Ganda <span class="cenas"><a href="original-moses2.html" target="_blank">Moses</a></span>! 

Answer 2

$lines = explode("\n", $content); 
$lines[0] = stri_replace("keyword", "replacement", $lines[0]); 
$content = implode("\n", $lines); 

，或者如果你明確要使用正則表達式

$lines = explode("\n", $content); 
$lines[0] = preg_replace("/keyword/i", "replacement", $lines[0]); 
$content = implode("\n", $lines); 

Answer 3

考慮使用HTML解析庫，而不是一個正則表達式，如simplehtmldom。您可以使用它來更新特定HTML標記的內容（因此，忽略不想更改的內容）。那麼你不必使用正則表達式;只要你過濾了適當的標籤，就可以使用像str_replace這樣的功能。

Answer 4

$str = preg_replace('~Moses(?!(?>[^<]*(?:<(?!/?a\b)[^<]*)*)</a>)~i', 
        '<a href="novo-mega-link.php">$0</a>', $str); 

負先行內的表達式匹配到下一個閉合</a>標籤，但前提是不是先看到開頭<a>標籤。如果成功，則表示單詞Moses位於錨點元素內，所以預覽失敗，並且不會發生匹配。

這是demo。