Is there a way to negate the presence of specific characters or sequences, such as "<!--", when using regular expressions to extract placeholder elements in PHP?

When using regular expressions to extract placeholder elements in PHP, you can negate the presence of specific characters or sequences by using negative lookaheads or lookbehinds in your regex pattern. This allows you to exclude certain characters or sequences from being matched. In the case of excluding "<!--", you can use a negative lookahead assertion to ensure that "<!--" is not part of the match. 

$input = &quot;&lt;div&gt;&lt;!-- This is a comment --&gt;This is some text&lt;/div&gt;&quot;;
$pattern = &#039;/(?&lt;!&lt;!--)placeholder(?![^&gt;]*--&gt;)/&#039;;
preg_match_all($pattern, $input, $matches);
print_r($matches[0]);

Keywords

regular expressions negation placeholder elements PHP specific characters

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