Online PHP editor | refs for GNEcZ

<?php $season_data = [ 'Paul' => [ 'Season' => [2014, 2015, 2016] ], 'John' => [ 'Season' => [2012] ] ]; $appearance_data = [ 'Paul' => [ 'Appearance'=> [ 2014, 2014, 2014, 2014, 2014, 2014, 2014, 2014, 2015, 2015, 2015 ] ], 'John' => [ 'Appearance' => [ 2012, 2012, 2012, 2012 ] ] ]; foreach ($season_data as $person => $data) { $defaults = array_fill_keys($data['Season'], 0); $result[$person]['SeasonCounts'] = array_replace( $defaults, array_count_values( array_intersect( $appearance_data[$person]['Appearance'], $data['Season'] ) ) ); } var_export($result);