How to compose a regular expression to select a string outside of the specified tags?

Question

PHP

Source line:

Lorem <a href="/article/2020">ipsum dolor</a> sit amet, consectetur adipiscing elit. 
Lorem ipsum dolor sit amet, consectetur adipiscing elit. 
Lorem ipsum dolor sit amet, consectetur adipiscing elit.

You need to select all occurrences of " ipsum dolor " that are outside the a
tag. After replacing with links, you should get:

Lorem <a href="/article/2020">ipsum dolor</a> sit amet, consectetur adipiscing elit. 
Lorem <a href="/article/9000">ipsum dolor</a> sit amet, consectetur adipiscing elit. 
Lorem <a href="/article/9000">ipsum dolor</a> sit amet, consectetur adipiscing elit.

Answer 1

https://regex101.com/r/oT14be/1

$text = preg_replace(
    '#<a\b.*?</a>(*SKIP)(*F)|ipsum dolor#s', 
    '<a href="/article/2020">$0</a>',
    $text
);