Merge an array with an existing array php

Question

I have two array both containing data. I want to be able to add them together so that the information from the second array joins into the first array. Currently the array_merge that I am doing adds the second array to the end of the first one.

Array 1

[1] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 16.11
            [4] => 80.56
            [5] => 96.67
        )
[2] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 1.23
            [4] => 50.69
            [5] => 14.24
        )

Array 2

[1] => Array
        (
            [0] => TIME
            [1] => Lorem
            [2] => Ipsum
        )

[2] => Array
        (
            [0] => TIME
            [1] => Some
            [2] => Text

        )

How can I Merge the two arrays so the output becomes like below?

Array 3

[1] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 16.11
            [4] => 80.56
            [5] => 96.67
            [6] => TIME
            [7] => Lorem
            [8] => Ipsum
        )
[2] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 1.23
            [4] => 50.69
            [5] => 14.24
            [6] => TIME
            [7] => Some
            [8] => Text
        )

What is currently happening

[1] => Array
        (
            [0] => 2017-07-14 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 16.11
            [4] => 80.56
            [5] => 96.67
        )

    [2] => Array
        (
            [0] => 2017-07-14 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 1.23
            [4] => 50.69
            [5] => 14.24
        )

    [3] => Array
        (
            [0] => TIME
            [1] => Lorem
            [2] => Ipsum
        )

    [4] => Array
        (
            [0] => TIME
            [1] => Some
            [2] => Text
        )

I have tried array_merge( $array1 , $array2 ); but that adds the second array to the end of the first one.

Any ideas?

Answer 1

This looks pretty forward to me, you simply array_merge() the elements of those two arrays:

<?php
$A = [
    1 => [
        '2017-07-13 00:00:00',
        'Foo',
        'Bar',
        16.11,
        80.56,
        96.67
    ],
    2 => [
        '2017-07-13 00:00:00',
        'Foo',
        'Bar',
        1.23,
        50.69,
        14.24
    ]
];
$B = [
    1 => [
        'TIME',
        'Lorem',
        'Ipsum'
    ],
    2 => [
        'TIME',
        'Some',
        'Text'
    ]
];

array_walk($B, function($values, $key) use (&$A) {
    $A[$key] = array_merge($A[$key], $values);
});
print_r($A);

The output of that obviously is:

Array
(
    [1] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 16.11
            [4] => 80.56
            [5] => 96.67
            [6] => TIME
            [7] => Lorem
            [8] => Ipsum
        )

    [2] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 1.23
            [4] => 50.69
            [5] => 14.24
            [6] => TIME
            [7] => Some
            [8] => Text
        )
)

---

UPDATE:

In the comment below you ask if this approach can be generalized to merge an arbitrary number of arrays. Sure that is possible, you just add another iteration layer:

<?php
$target = [
    1 => ['2017-07-13 00:00:00', 'Foo', 'Bar', 16.11, 80.56, 96.67],
    2 => ['2017-07-13 00:00:00', 'Foo', 'Bar', 1.23, 50.69, 14.24]
];
$sources = [
    'B' => [
        1 => ['TIME', 'Lorem', 'Ipsum'],
        2 => ['TIME', 'Some', 'Text']
    ],
    'C' => [
        1 => ['C1a', 'C1b'],
        2 => ['C2a', 'C2b', 'C2b']
    ]
];

array_walk($sources, function($source) use (&$target) {
    array_walk($source, function($values, $key) use (&$target) {
        $target[$key] = array_merge($target[$key], $values);
    });
});
print_r($target);

This variant produces that output:

Array
(
    [1] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 16.11
            [4] => 80.56
            [5] => 96.67
            [6] => TIME
            [7] => Lorem
            [8] => Ipsum
            [9] => C1a
            [10] => C1b
        )

    [2] => Array
        (
            [0] => 2017-07-13 00:00:00
            [1] => Foo
            [2] => Bar
            [3] => 1.23
            [4] => 50.69
            [5] => 14.24
            [6] => TIME
            [7] => Some
            [8] => Text
            [9] => C2a
            [10] => C2b
            [11] => C2b
        )

)