用例外替换重复字符

Question

How can you translate this into Regex: Replace any char (aka '.') that is repeating more than once and replace it with one of that char with the exception of "ii" and "iii".

$reg = preg_replace('/(.)/1{1,}/','', $string);

Now this must replace VVVVV with V or .... with . and must not replace Criiid (or Criid) but Criiiiiiid with Crid.

Feel free to comment if you don't understand the question.

Answer 1

preg_replace('/([^i])\1+|(i){4,}/', '\1\2', $string)

Note that this will squeeze everything -- spaces, newlines, etc.