How can lookaheads be used in regular expressions to avoid matching empty attribute values in PHP?

Lookaheads can be used in regular expressions in PHP to ensure that empty attribute values are not matched. By using a negative lookahead assertion, we can specify that the attribute value must contain at least one character, preventing empty values from being matched. This can be particularly useful when parsing HTML or XML content where attributes may have empty values. 

$pattern = '/\battribute="(?!\s*")([^"]*)"/';
$string = 'attribute="" attribute="value"';
preg_match_all($pattern, $string, $matches);
print_r($matches[0]);

Keywords

lookaheads regular expressions empty attribute values matching PHP

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