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<?php $ary1 = array( array( 'sn' => '123', 'name' => 'whatever', ), array( 'sn' => '234', 'name' => 'whatever', ), ); $ary2 = array( array( 'sn' => '123', 'gender' => 'male', ), array( 'sn' => '234', 'gender' => 'female', ), ); $res = []; foreach (array_merge($ary1, $ary2) as $a) { $res[$a['sn']] = array_merge($res[$a['sn']] ?? $a, $a); } var_dump($res);

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42.75 ms | 402 KiB | 5 Q