基于特定密钥PHP合并数组

Question

Array
(
    [0] => Array
        (
            [employee] => 15
            [first_name] => Person1
            [surname] => Person1
            [totaltime] => 183.75
            [FirstValue] => 1
        )

[1] => Array
    (
        [employee] => 15
        [first_name] => Person1
        [surname] => Person1
        [totaltime] => 183.75
        [SecondValue] => 2            
    )
)

I want output like this

Array
(
    [0] => Array
        (
            [employee] => 15
            [first_name] => Person1
            [surname] => Person1
            [totaltime] => 183.75
            [FirstValue] => 1
            [SecondValue] => 2
        )
)

I have a multi-dimensional array. Each element has an employee as key which can be the same or different. I want to merge the arrays with the same EmployeeID. Also 2 same employee may have different elements like FirstValue,SecondValue, etc. I want to merge unique element as I've show in the above output.

Answer 1

$arr = Array(
   Array
        (
            employee => 15,
            first_name => 'Person1',
           surname => 'Person1',
            totaltime => 183.75,
            FirstValue => 1
        ),
 Array
    (
        employee=> 15,
        first_name => Person1,
        surname=> Person1,
        totaltime => 183.75,
        SecondValue => 2            
    ),
       Array
        (
            employee => 16,
            first_name => 'Person1',
           surname => 'Person1',
            totaltime => 183.75,
            FirstValue => 1
        ));

$ids = array();                            // array employee => key

foreach($arr as $key => &$item)
   if(isset($ids[$item['employee']])) {    // is there such employee in ids
      $arr[$ids[$item['employee']]] =      // yes - add values from current item
          array_replace($arr[$ids[$item['employee']]], $item);  
      unset($arr[$key]);                   // and remove it from array
   }
   else $ids[$item['employee']] = $key;    // save current key

print_r($arr);

result

Array
(
    [0] => Array
        (
            [employee] => 15
            [first_name] => Person1
            [surname] => Person1
            [totaltime] => 183.75
            [FirstValue] => 1
            [SecondValue] => 2
        )

    [2] => Array
        (
            [employee] => 16
            [first_name] => Person1
            [surname] => Person1
            [totaltime] => 183.75
            [FirstValue] => 1
        )

)