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run code in 300+ PHP versions simultaneously
; <?php $arrays = array( 0 => array( 0 => 'one', 1 => 'two', 2 => 'three' ), 1 => array( 0 => 'four', 1 => 'five', 2 => 'six' ), 2 => array( 0 => 'seven', 1 => 'eight', 2 => 'nine' ) ); print_r(array_reduce($arrays, function($carry, $item) { $carry += $item; return $carry; }, []));

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39.65 ms | 402 KiB | 5 Q