php - Add to array consecutive numbers -

this first question so, hope right. in php (if can't, python or pseudo language okay), given array of n elements:

old_array = [1, 2, 3, 5, 7, 8, 9, 20, 21, 23, 29] 

i need add new array consecutive numbers, if not consecutive number add value new array:

new_array = [ [1,2,3],               [5],               [7,8,9]               [20,21]               [23],               [29]             ] 

here on so, found these related topics, can't work.

1. creating list of lists consecutive numbers
2. python finding n consecutive numbers in list
3. find sum of consecutive whole numbers w/o using loop in javascript

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the code wasn't working on version history, removed because it's having formatting problems.

thanks all, , juan, mistabell , axsuul providing correct answer.

the best can came is:

function subsequencearray($values) {     $res = array();     $length = count($values);     if (0 == $length) {         return $res;     }     $last = 0;     $res[$last] = array($values[0]);     ($i = 1; $i < $length; $i++) {         if ($values[$i] == $values[$i-1] + 1) {             $res[$last][] = $values[$i];         } else {             $res[++$last] = array($values[$i]);         }     }     return $res; }