压缩函数从字符串中删除双字母（PHP）

Question

I need to take every double letter occurrence away from a word. (I.E. "attached" have to become: "aached".)

I wrote this function:

function strip_doubles($string, $positions) {
for ($i = 0; $i < strlen($string); $i++) {
    $stripped_word[] = $string[$i];
}   
foreach($positions['word'] as $position) {      
    unset($stripped_word[$position], $stripped_word[$position + 1]);
}
$returned_string= "";   
foreach($stripped_words $key => $value) {
    $returned_string.= $stripped_words[$key];
}
return $returned_string;
}

where $string is the word to be stripped and $positions is an array containing the positions of any first double letter.

It perfectly works but how would a real programmer write the same function... in a more condensed way? I have a feeling it could be possible to do the same thing without three loops and so much code.

Answer 1

Non-regex solution, tested:

$string = 'attached';
$stripped = '';
for ($i=0,$l=strlen($string);$i<$l;$i++) {
    $matched = '';
    // if current char is the same as the next, skip it
    while (substr($string, $i, 1)==substr($string, $i+1, 1)) {
        $matched = substr($string, $i, 1);
        $i++;
    }
    // if current char is NOT the same as the matched char, append it
    if (substr($string, $i, 1) != $matched) {
        $stripped .= substr($string, $i, 1);
    }
}
echo $stripped;