PHP 多维数组按值排序

Question

Regarding this multidimensional array:

[
(int) 7 => [
    (int) 0 => [
        (int) 0 => '12:45',
        (int) 1 => 'E1',
        (int) 2 => 'B EXTREME 30'
    ],
    (int) 1 => [
        (int) 0 => '10:15',
        (int) 1 => 'E1',
        (int) 2 => 'B SHAPE 30'
    ],
],
(int) 1 => [
    (int) 0 => [
        (int) 0 => '09:30',
        (int) 1 => 'E2',
        (int) 2 => 'CYCLING VIRTUAL 50'
    ],
    (int) 1 => [
        (int) 0 => '10:30',
        (int) 1 => 'E1',
        (int) 2 => 'BODY PUMP VIRTUAL 60'
    ],
    (int) 2 => [
        (int) 0 => '11:45',
        (int) 1 => 'E1',
        (int) 2 => 'BODY BALANCE VIRTUAL 60'
    ],
],
(int) 2 => [
    (int) 0 => [
        (int) 0 => '14:45',
        (int) 1 => 'E2',
        (int) 2 => 'CYCLING VIRTUAL 50'
    ],
    (int) 1 => [
        (int) 0 => '17:00',
        (int) 1 => 'E1',
        (int) 2 => 'POSTURA ALONGAMENTO 60'
    ],
    (int) 2 => [
        (int) 0 => '09:15',
        (int) 1 => 'E1',
        (int) 2 => 'BODY PUMP 50'
    ],
]
]

The first key, of each first level array, are days of the week (day 7, day 1 and day 2).

The arrays inside each first level array contain hour ( 09:45 ), rooms ( E1 ) and description ( B EXTREME 30 ).

I tried to sort this multidimensional array by the second levels array hour value. I used usort() , ksort() , array_multisort() , and some custom made functions for sorting the array as i need without luck.

The inside arrays must be sorted by ascending order, like this (example with day 2):

09:15 -> 14:45 -> 17:00

Does anyone knows how can i achieve this?

Answer 1

Assuming your data is called $data . Iterate the outer array, and apply a sort on each mid-level array, based on the time-part (in the innermost arrays). As your times are always formatted as "hh:ss", a string comparison in the usort callback does the job:

foreach ($data as &$events) {
    usort($events, function($a, $b) {
        return strcmp($a[0], $b[0]);
    });
}

Note the & in the foreach : this makes sure you sort the original data, and not a copy of it.

If you want to create a new array, let's say $result , then do this (no & here!):

foreach ($data as $day => $events) {
    usort($events, function($a, $b) {
        return strcmp($a[0], $b[0]);
    });
    $result[$day] = $events;
}

Answer 2

usort — Sort an array by values using a user-defined comparison function. Lets create a function where we compare time of two events.

This is part of your array

$array = [
    2 => [
        0 => [
            0 => '14:45',
            1 => 'E2',
            2 => 'CYCLING VIRTUAL 50'
        ],
        1 => [
            0 => '17:00',
            1 => 'E1',
            2 => 'BODY PUMP VIRTUAL 60'
        ],
        2 => [
            0 => '09:15',
            1 => 'E1',
            2 => 'BODY BALANCE VIRTUAL 60'
        ],
    ],
];

This is an example how to sort items for one day (day 2)

usort($array[2], function ($a, $b) {
    $time_a = strtotime($a[0]); // convert string to a unix timestamp to compare int
    $time_b = strtotime($b[0]);
    return $time_a - $time_b;
});

Output using print_r($array);

Array
(
    [2] => Array
        (
            [0] => Array
                (
                    [0] => 09:15
                    [1] => E1
                    [2] => BODY BALANCE VIRTUAL 60
                )

            [1] => Array
                (
                    [0] => 14:45
                    [1] => E2
                    [2] => CYCLING VIRTUAL 50
                )

            [2] => Array
                (
                    [0] => 17:00
                    [1] => E1
                    [2] => BODY PUMP VIRTUAL 60
                )

        )

)

To sort all days we do in a loop, passing each day array as a reference using & :

foreach ($array as &$day) {
    usort($day, function ($a, $b) {
        $time_a = strtotime($a[0]);
        $time_b = strtotime($b[0]);
        return $time_a - $time_b;
    });
}