3v4l.org

run code in 300+ PHP versions simultaneously
<?php $collection = [ [1 => 10.0, 2 => 20.0, 3 => 50.0, 4 => 80.0, 5 => 100.0], [3 => 20.0, 5 => 20.0, 6 => 100.0, 7 => 10.0], [1 => 30.0, 3 => 30.0, 5 => 10.0, 8 => 10.0] ]; var_export( array_reduce( array_keys( array_intersect_ukey( ...array_merge( $collection, [fn($a, $b) => $a <=> $b] ) ) ), fn($result, $k) => $result + [$k => array_sum(array_column($collection, $k)) / count($collection)], [] ) );
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
array ( 3 => 33.333333333333336, 5 => 43.333333333333336, )

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