Online PHP editor | output for a0Cfa

<?php $array = [ ['A' => 'O', 'B' => 'O', 'C' => 1, 'count' => 1], ['A' => 'Test', 'B' => 'Test', 'C' => 1, 'count' => 1], ['A' => 'O', 'B' => 'O', 'C' => 1, 'count' => 1], ['A' => 'Test', 'B' => 'Test', 'C' => 1, 'count' => 1], ['A' => 'Test', 'B' => 'test1', 'C' => 2, 'count' => 1], ]; $result = []; foreach ($array as $row) { $key = implode('~', array_slice($row, 0, 3)); if (!isset($result[$key])) { $result[$key] = $row; } else { $result[$key]['count'] += $row['count']; } } var_export(array_values($result));