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Accepted
Vera Canet
Asked: 2020-05-05 07:42:00 +0800 CST 2020-05-05 07:42:00 +0800 CST

How to sort an array of objects by one of its elements [PHP]

  • 772

At the present time I find that I am unable to order an array of objects using one of its keys as an index to order.

Let's say the array comes like this:

Array
(
    [0] => stdClass Object
        (
            [Id] => e6930148-319f-4b87-bb57-8aae98adfc55
            [State] => FINISHED
            [StartDate] => 2018-05-03T08:57:30+02:00
            [EndDate] => 2018-05-03T08:59:17+02:00
        )
    [1] => stdClass Object
        (
            [Id] => 4263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2018-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

And what I need is for all the results to be ordered by the value of StartDate and descending, to always have the most recent as the first record.

I have tried generating a compare function

  function comp($a, $b) {
    if ($a < $b) return true;
    else return false;
  }

Generating a new array with the data I get

  foreach ($json as $datos) {
    $id = $datos->Id;
    $estado = $datos->State;
    $fechaIni = $datos->StartDate;
    $fechaFin = $datos->EndDate;
    $proceso = $datos->Configuration->ProcessId;

    array_push($arrayDatos, $datos)
  }

And calling her later from a uksort

  uksort($arrayDAtos, comp(xxxx,yyyy))

But this is where I think I'm confused, because I don't know how to pass the necessary values ​​to the comp function so that it orders by StartDate.

Come on, I have nothing clear about how uksort works or what exactly the comp function should do

php

2 Answers

  1. Best Answer

    You can indeed use usort, if you don't mind the (numeric) indices of the new array changing, otherwise you could use uasort. Both functions admit a function as a parameter where we indicate how we want the order. In this case we will use our object_sorter.

    I propose this function, somewhat advanced and certainly improvable, which offers the following advantages:

    • You can re-use it to order by any key of the object that is passed in parameter
    • It supports an optional order parameterDESC ( ), for when you want to order DESCindentally.
    • Use strnatcmp, taking advantage of its advantages, to make the comparisons.

    The function is simply this:

    function object_sorter($clave,$orden=null) {
    return function ($a, $b) use ($clave,$orden) {
          $result=  ($orden=="DESC") ? strnatcmp($b->$clave, $a->$clave) :  strnatcmp($a->$clave, $b->$clave);
          return $result;
    };
}

    And to use it, you just pass it the array.

    • To order it ASCendently by key StarDate:

      usort($objDatos, object_sorter('StartDate'));

    • To order it DESCendently by key StarDate:

      usort($objDatos, object_sorter('StartDate','DESC'));

    Full test:

    VER DEMO EN REXTESTER

    <?php
/*PHP: Ordenar array de objetos por uno de sus miembreos con usort - https://es.stackoverflow.com/q/161586/29967*/ 
/*Función*/
function object_sorter($clave,$orden=null) {
    return function ($a, $b) use ($clave,$orden) {
          $result=  ($orden=="DESC") ? strnatcmp($b->$clave, $a->$clave) :  strnatcmp($a->$clave, $b->$clave);
          return $result;
    };
}

/*Objeto original*/

    $objDatos = 
        array(
                0 => (object) array(
                                    'Id' => 'e6930148-319f-4b87-bb57-8aae98adfc55',
                                    'State' => 'FINISHED',
                                    'StartDate' => '2019-05-03T08:57:30+02:00',
                                    'EndDate' => '2018-05-03T08:59:17+02:00'      
                                   ),
                1 => (object) array(
                                    'Id' => '4263f6a9-6e49-4aee-bcf6-70e1d2578fc5',
                                    'State' => 'FINISHED',
                                    'StartDate' => '2018-05-03T10:15:39+02:00',
                                    'EndDate' => '2018-05-03T10:15:58+02:00'      
                                   ),
                3 => (object) array(
                                    'Id' => '5263f6a9-6e49-4aee-bcf6-70e1d2578fc5',
                                    'State' => 'FINISHED',
                                    'StartDate' => '2020-05-03T10:15:39+02:00',
                                    'EndDate' => '2018-05-03T10:15:58+02:00'      
                                   ),            
            );

/*Original*/
echo "OBJETO ORIGINAL:".PHP_EOL.PHP_EOL;
print_r($objDatos);


/*Orden por defecto (ASCendente)*/
usort($objDatos, object_sorter('StartDate'));
echo PHP_EOL.PHP_EOL."ORDEN ASCENDENTE:".PHP_EOL.PHP_EOL;
print_r($objDatos);


/*Orden DESCendente (indicándolo en parámetro)*/
usort($objDatos, object_sorter('StartDate','DESC'));
echo PHP_EOL.PHP_EOL."ORDEN DESCENDENTE:".PHP_EOL.PHP_EOL;
print_r($objDatos);


?>

    Result:

    ORIGINAL ITEM:

    Array
(
    [0] => stdClass Object
        (
            [Id] => e6930148-319f-4b87-bb57-8aae98adfc55
            [State] => FINISHED
            [StartDate] => 2019-05-03T08:57:30+02:00
            [EndDate] => 2018-05-03T08:59:17+02:00
        )

    [1] => stdClass Object
        (
            [Id] => 4263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2018-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

    [3] => stdClass Object
        (
            [Id] => 5263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2020-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

)

    ASCENDING ORDER:

    Array
(
    [0] => stdClass Object
        (
            [Id] => 4263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2018-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

    [1] => stdClass Object
        (
            [Id] => e6930148-319f-4b87-bb57-8aae98adfc55
            [State] => FINISHED
            [StartDate] => 2019-05-03T08:57:30+02:00
            [EndDate] => 2018-05-03T08:59:17+02:00
        )

    [2] => stdClass Object
        (
            [Id] => 5263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2020-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

)

    DESCENDING ORDER:

    Array
(
    [0] => stdClass Object
        (
            [Id] => 5263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2020-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

    [1] => stdClass Object
        (
            [Id] => e6930148-319f-4b87-bb57-8aae98adfc55
            [State] => FINISHED
            [StartDate] => 2019-05-03T08:57:30+02:00
            [EndDate] => 2018-05-03T08:59:17+02:00
        )

    [2] => stdClass Object
        (
            [Id] => 4263f6a9-6e49-4aee-bcf6-70e1d2578fc5
            [State] => FINISHED
            [StartDate] => 2018-05-03T10:15:39+02:00
            [EndDate] => 2018-05-03T10:15:58+02:00
        )

)

    I hope it is useful for you.

    NOTE: Function that we can adapt, improve and incorporate into our utility code library.

    • 6

  2. You can do it using usort like so:

    function date_compare($a, $b)
{
    $t1 = strtotime($a['startDate']);
    $t2 = strtotime($b['startDate']);
    return $t1 - $t2;
}    
usort($arrayDatos, 'date_compare');
    • 1