匹配子字符串的子字符串

Question

Input:

Animal {cow.<span>moo</span>} <span>noises</span>

Output:

Animal {cow.moo} <span>noises</span>

How could I match only the <span> inside the braces for replacement? I have got as far as matching everything between the braces with

(?<=\{)(.*?)(?=\})

Any help would be greatly appreciated.

Answer 1

You may use a preg_replace_callback to match the strings in between {...} with a basic regex like '~{[^}]+}~' and then replace what you need inside the callback function:

$s = 'Animal {cow.<span>moo</span>} <span>noises</span>';
echo preg_replace_callback('~{[^}]+}~', function($m) {
    return str_replace(["<span>", "</span>"], "", $m[0]);
}, $s);
// => Animal {cow.moo} <span>noises</span>

See the PHP demo.

You may use a preg_replace inside the callback function if you need to replace with a regex.