弹出并从一个关联数组推送到另一个数组

Question

I want to pop from array2 and want to push in array1. But according to some custom requirement.

Now in array1 there is 1st key's readingOrder is 1 and 2nd key's readingOrder is 4.

So i want to push between this two key from array2's first two key.And same process for all other.

and my final array must be like array3.

for example in array1 key[0] readingOrder is 1 and key[1]'s 4. Now i want to push another two key from array2. for array1 key[2] reading order is 6. so before this key i want to push another one key from array2 and same for further...

array1 is like below

Array
(
    [0] => Array
        (
            [readingOrder] => 1
            [id] => 78
        )

    [1] => Array
        (
            [readingOrder] => 4
            [id] => 76
        )

    [2] => Array
        (
            [readingOrder] => 6
            [id] => 80
        )

)

array2 is like below

Array
(
    [0] => Array
        (
            [id] => 81
            [readingOrder] => 2
        )

    [1] => Array
        (
            [id] => 82
            [readingOrder] => 5
        )

    [2] => Array
        (
            [id] => 84
            [readingOrder] => 7
        )

    [3] => Array
        (
            [id] => 85
            [readingOrder] => 8
        )

    [4] => Array
        (
            [id] => 86
            [readingOrder] => 9
        )

    [5] => Array
        (
            [id] => 87
            [readingOrder] => 10
        )

    [6] => Array
        (
            [id] => 88
            [readingOrder] => 11
        )

)

Output array3:

Array
(
    [0] => Array
        (
            [readingOrder] => 1
            [id] => 78
        )

    [1] => Array
        (
            [id] => 81
            [readingOrder] => 2
        )

    [2] => Array
        (
            [id] => 82
            [readingOrder] => 5
        )

    [3] => Array
        (
            [readingOrder] => 4
            [id] => 76
        )

    [4] => Array
        (
            [id] => 84
            [readingOrder] => 7
        )

    [5] => Array
        (
            [readingOrder] => 6
            [id] => 80
        )

    [6] => Array
        (
            [id] => 85
            [readingOrder] => 8
        )

    [7] => Array
        (
            [id] => 86
            [readingOrder] => 9
        )

    [8] => Array
        (
            [id] => 87
            [readingOrder] => 10
        )

    [9] => Array
        (
            [id] => 88
            [readingOrder] => 11
        )

)

Thanks..

Answer 1

You can do this with usort. First you need to merge the arrays:

$a1 = [
    [
        'readingOrder' => 1,
        'id' => 78
    ],
    [
        'readingOrder' => 4,
         'id' => 76
    ],
    [
        'readingOrder' => 6,
        'id' => 80
    ]
];
$a2 = [
    [
        'readingOrder' => 2,
        'id' => 81
    ],
    [
        'readingOrder' => 5,
        'id' => 82
    ],
    [
        'readingOrder' => 7,
        'id' => 84
    ],
    [
        'readingOrder' => 8,
        'id' => 85
    ]
];

$a3 = array_merge($a1, $a2);

Then you need to use usort:

usort($a3, function($a,$b) {
    if ($a['readingOrder'] == $b['readingOrder']) return 0;
    return $a['readingOrder'] < $b['readingOrder'] ? -1 : 1;
});

In PHP 7 you can now use the spaceship operator, which would make the code more clean. Like so:

usort($a3, function($a,$b) {
    return $a[0] <=> $b[0];
});

This will then return:

(
    [0] => Array
        (
            [readingOrder] => 1
            [id] => 78
        )

    [1] => Array
        (
            [readingOrder] => 2
            [id] => 81
        )

    [2] => Array
        (
            [readingOrder] => 4
            [id] => 76
        )

    [3] => Array
        (
            [readingOrder] => 5
            [id] => 82
        )

    [4] => Array
        (
            [readingOrder] => 6
            [id] => 80
        )

    [5] => Array
        (
            [readingOrder] => 7
            [id] => 84
        )

    [6] => Array
        (
            [readingOrder] => 8
            [id] => 85
        )

)