PHP Regex 匹配字符串中的单词，不包括一个特定单词

Question

我有一个文本($txt)，一个单词数组($words)我想添加一个链接和一个不能被替换的单词($wordToExclude)。

$words = array ('adipiscing','molestie','fringilla');
$wordToExclude = 'consectetur adipiscing';


$txt = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque
mattis tincidunt dolor sed consequat. Sed rutrum, mauris convallis bibendum 
dignissim, ligula sem molestie massa, vitae condimentum neque sem non tellus.
Aenean dolor enim, cursus vel sodales ac, condimentum ac erat. Quisque
lobortis libero nec arcu fringilla imperdiet. Pellentesque commodo, 
arcu et dictum tincidunt, ipsum elit molestie ipsum, ut ultricies nisl
neque in velit. Curabitur luctus dui id urna consequat vitae mattis
turpis pretium. Donec nec adipiscing velit.'

我想得到这个结果:

$txt = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque
mattis tincidunt dolor sed consequat. Sed rutrum, mauris convallis bibendum 
dignissim, ligula sem <a href="#">molestie</a> massa, vitae condimentum neque sem non tellus.
Aenean dolor enim, cursus vel sodales ac, condimentum ac erat. Quisque
lobortis libero nec arcu <a href="#">fringilla</a> imperdiet. Pellentesque commodo, 
arcu et dictum tincidunt, ipsum elit <a href="#">molestie</a> ipsum, ut ultricies nisl
neque in velit. Curabitur luctus dui id urna consequat vitae mattis
turpis pretium. Donec nec <a href="#">adipiscing</a> velit.'

Answer 1

$result = preg_replace(
    '/\b                 # Word boundary
    (                    # Match one of the following:
     (?<!consectetur\s)  #  (unless preceded by "consectetur "
     adipiscing          #  adipiscing
    |                    # or
     molestie            #  molestie
    |                    # etc.
     fringilla
    )                    # End of alternation
    \b                   # Word boundary
    /ix', 
    '<a href="#">\1</a>', $subject);