如何通过子数组值对多维数组进行分组并在PHP中重新分配键

Question

I looked at all the similar questions and samples (there are many) but still can't get this to work (though I think I am close).

I have an array of employee schedules pulled from a text file...

schedule.txt:

    123,Joe,20120208,0845,1645
    123,Joe,20120209,0800,1600
    456,Sue,20120208,0900,1700
    456,Sue,20120209,0700,1500
    ...

My code to generate the array is:

    $schedule = file_get_contents('./schedule.txt');
    $s = explode("
", $schedule);
    for ($i = 0; $i < count($s); $i++) {
        $s[$i] = explode(",", $s[$i]);
    }
    print_r($s);

Output is:

    Array
    (
        [0] => Array
            (
                [0] => 123
                [1] => Joe
                [2] => 20120208
                [3] => 0845
                [4] => 1645
            )

        [1] => Array
            (
                [0] => 123
                [1] => Joe
                [2] => 20120209
                [3] => 0800
                [4] => 1600
            )

        [2] => Array
            (
                [0] => 456
                [1] => Sue
                [2] => 20120208
                [3] => 0900
                [4] => 1700
            )

        [3] => Array
            (
                [0] => 456
                [1] => Sue
                [2] => 20120209
                [3] => 0700
                [4] => 1500
            )
    )

I am instead trying to group employees by Id in a new multidimensional array with output like this:

    Array
    (
        [123] => Array
            (
                [0] => Array
                    (
                        [0] => Joe
                        [1] => 20120208
                        [2] => 0845
                        [3] => 1645
                    )

                [1] => Array
                    (
                        [0] => Joe
                        [1] => 20120209
                        [2] => 0800
                        [3] => 1600
                    )
            )

        [456] => Array
            (
                [0] => Array
                    (
                        [0] => Sue
                        [1] => 20120208
                        [2] => 0900
                        [3] => 1700
                    )

                [1] => Array
                    (
                        [0] => Sue
                        [1] => 20120209
                        [2] => 0700
                        [3] => 1500
                    )
            )
    )

I cannot for the life of me wrap my head around how to change my existing array into this new (different) output... I am trying this but getting nowhere:

    $newArr = array();

    foreach($s as $k => $v) {
        if(!isset($newArr[$v[0]])) {
            $newArr[$v[0]] = array();
        }

        $newArr[$v[0]][] = array($v[0]);
    }

Though my output is now:

    Array
    (
        [123] => Array
            (
                [0] => Array
                    (
                        [0] => 123
                    )

                [1] => Array
                    (
                        [0] => 123
                    )
            )

        [456] => Array
            (
                [0] => Array
                    (
                        [0] => 456
                    )

                [1] => Array
                    (
                        [0] => 456
                    )
            )
    )

Any thoughts? I know I am missing something in my code around the line:

    $newArr[$v[0]][] = array($v[0]);

I tried changing it to:

    $newArr[$v[0]][] = array(0 => $v[1], 1 => $v[2], 2 => $v[3], 3 => $v[4]);

which gives my the right output, but I now get undefined offset errors. Plus, if the number of keys in the sub array changes, this code is now limited to the 4 I explicitly entered...

Answer 1

this should be enough, if I understood you right :)

$lines = file('./schedule.txt');

$employees = array();
foreach ($lines as $line)
{
    $chunks = explode(',', $line);
    $employees[$chunks[0]][] = array_slice($chunks, 1);
}

print_r($employees);