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run code in 300+ PHP versions simultaneously
<?php $array = [ [ ['name' => 'john', 'age' => 10,], ['name' => 'mary', 'age' => 15,], ], [ ['name' => 'mark', 'age' => 12,], ['name' => 'susan', 'age' => 8,], ] ]; var_export( array_column( array_merge(...$array), 'age' ) );

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