How to merge two multi array without duplicates in PHP

Question

I'm trying to merge two Multiple Arrays.

Both arrays have the same item({ "ort": "rom", "lioc": "inrom" }).

    $test_1 =  '
    {
        "hotels" : { 
            "hotel" : [
                { "ort": "rom", "lioc": "inrom" },
                { "ort": "paris", "lioc": "inpsrisd" },
                { "ort": "berlin", "lioc": "inberlin" },
                { "ort": "milano", "lioc": "inmilano" },
                { "ort": "paris", "lioc": "anotherinpsrisd" },
                { "ort": "muc", "lioc": "inmuc" }
            ]
        }
    }
    ';
    $test_2 =  '
    {
        "hotels" : { 
            "hotel" : [
                { "ort": "rom", "lioc": "inrom" },
                { "ort": "beijing", "lioc": "wanda" }
            ]
        }
    }
    ';
    
    $arr_test1 = json_decode($test_1, TRUE);
    $arr_test2 = json_decode($test_2, TRUE);

    var_dump(json_encode(array_merge_recursive($arr_test1, $arr_test2)));
    var_dump(json_encode(array_unique(array_merge($arr_test1,$arr_test2), SORT_REGULAR)));

If I run this code then I get the following results.

result1:
{
    "hotels" : { 
        "hotel" : [
            { "ort": "rom", "lioc": "inrom" },
            { "ort": "paris", "lioc": "inpsrisd" },
            { "ort": "berlin", "lioc": "inberlin" },
            { "ort": "milano", "lioc": "inmilano" },
            { "ort": "paris", "lioc": "anotherinpsrisd" },
            { "ort": "muc", "lioc": "inmuc" },
            {"ort":"rom","lioc":"inrom"},
            {"ort":"beijing","lioc":"wanda"}
        ]
    }
}

result2:
{
    "hotels" : { 
        "hotel" : [
            { "ort": "rom", "lioc": "inrom" },
            { "ort": "beijing", "lioc": "wanda" }
        ]
    }
}

Both are not my expected results.

As you can see in this screenshot { "ort": "rom", "lioc": "inrom" } item is duplicated in result1.

The point is that don't know what is array's keys are and don't know deep of the array.

I'd like to get the merged array without duplicated items like this.

{
    "hotels" : { 
        "hotel" : [
            { "ort": "rom", "lioc": "inrom" },
            { "ort": "paris", "lioc": "inpsrisd" },
            { "ort": "berlin", "lioc": "inberlin" },
            { "ort": "milano", "lioc": "inmilano" },
            { "ort": "paris", "lioc": "anotherinpsrisd" },
            { "ort": "muc", "lioc": "inmuc" },
            { "ort": "beijing", "lioc": "wanda" }
        ]
    }
}

How can I solve this?

vixducis · Accepted Answer · 2021-10-20 12:33:02Z

1

array_merge_recursive is actually a very good place to start, but it doesn't allow you to make the inner array unique. This could be achieved by using your own recursive unique implementation. An example of such a function

function recursiveUnique($input): array
{
    // if the input is not an array, just return the input
    if (!is_array($input)) {
        return $input;
    }
    // check if the array is a list or an associative array
    else if (count($input) === 0 || array_keys($input) === range(0, count($input) - 1)) {
        return array_values(array_unique($input, SORT_REGULAR));
    }
    else {
        foreach ($input as $key => $value) {
            $input[$key] = recursiveUnique($value);
        }
        return $input;
    }
}

If you feed the recursively merged array to this function, you should get your desired outcome. You can check the functionality in this 3v4l.

edited Oct 20, 2021 at 12:33

answered Oct 19, 2021 at 9:50

vixducis

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3 Comments

Web Star Over a year ago

Thank you for your attention for old my question. I agree with removing duplicated items after merging. However, in this way, there is key-value exists (example: "0", "1", ... "5", "7"). I just want to get an array with no index key. The point is that don't know deep the array. How about it?

vixducis Over a year ago

@Silverstar You can achieve that quite easily by wrapping the array_unique in an array_values. I adjusted my answer to reflect this. Does this answer your question?

Web Star Over a year ago

Certainly, your function is simpler and easy to understand than the function I have already created and implemented. Thank you.

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