Online PHP editor | output for G3gi0

<?php $array = [ ['model' => 'iPhone 12', 'grade' => 'A', 'price' => '100'], ['model' => 'iPhone 12', 'grade' => 'A', 'price' => '95'], ['model' => 'iPhone 12', 'grade' => 'B', 'price' => '85'], ['model' => 'iPhone 12', 'grade' => 'C', 'price' => '75'], ]; $result = []; foreach ($array as $row) { $compositeKey = $row['model'] . '_' . $row['grade']; if (!isset($result[$compositeKey]) || $result[$compositeKey][$row['grade']] > $row['price']) { $result[$compositeKey] = [ 'model' => $row['model'], $row['grade'] => $row['price'] ]; } } var_export(array_values($result));