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<?php $array =[203,204,204,203,203,205]; $i=-1; $prev = null; $new=[]; Foreach($array as $val){ If($val != $prev){ $i++; } if(!isset($new[$i][$val])){ $new[$i][$val] =1; }else{ $new[$i][$val]++; } $prev = $val; } var_dump($new);
Output for 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
array(4) { [0]=> array(1) { [203]=> int(1) } [1]=> array(1) { [204]=> int(2) } [2]=> array(1) { [203]=> int(2) } [3]=> array(1) { [205]=> int(1) } }

preferences:
131.33 ms | 408 KiB | 5 Q