preg_replace函數的字符串PHP不是取代的特殊字符

Question

$value['keyword']='P|$$';<br> 
$keyword = preg_quote($value['keyword'], '/');<br> 
$question = "verying P|$$ quedon";<br> 
echo $abc = preg_replace("/\b($keyword)\b/i",'<span style="color:red">$1</span>',$question);<br> 

我想串的紅顏色匹配關鍵字

Answer 1

$後的字邊界需要一個字字符出現後的很對，所以沒有更換回吐放置在這裏。

您需要更換用的(?<!\w)和(?!\w) lookarounds的幫助，如果關鍵字之前或之後用字字符將無法在比賽中定義明確的邊界字邊界：

$value['keyword']='P|$$'; 
$keyword = preg_quote($value['keyword'], '/'); 
$question = "verying P|$$ quedon"; 
echo $abc = preg_replace("/(?<!\w)($keyword)(?!\w)/i",'<span style="color:red">$1</span>',$question); 

見PHP demo