PHP Unique MultiDimensional Array Issue

Question

So, I am getting unique values from my MD array utilizing the following function:

    function unique_multidim_array($array, $key) { 
        $temp_array = array(); 
        $i = 0; 
        $key_array = array();           
        foreach( $array as $val ) { 
            if ( ! in_array( $val[$key], $key_array ) ) { 
                $key_array[$i] = $val[$key]; 
                $temp_array[$i] = $val; 
            }
            $i++; 
        } 
        return $temp_array; 
    }

My array is similar to the following:

Array (
    [0] =>
        Array (
            'name' => 'Nevada'
        )
    [1] =>
        Array (
            'name' => 'Colorado'
        )
    [2] =>
        Array (
            'name' => 'Nevada'
        )
    [3] =>
        Array (
            'name' => 'Colorado'
        )
    [4] =>
        Array (
            'name' => 'Oklahoma'
        )
    [5] =>
        Array (
            'name' => 'Nevada'
        )
    [6] =>
        Array (
            'name' => 'Nevada'
        )
)

And using the function (unique_multidim_array ( $term_arr, 'name' )) above I am getting a single Nevada and a single Colorado, however, it is not returning Oklahoma

What can I do to ensure that it will return unique values, even if there are no duplicates?

I can't reproduce your problem: phpfiddle.org/main/code/k8in-xv05 — Peter van der Wal
– Peter van der Wal, Commented Aug 25, 2017 at 15:55
Not sure if you can view this... but it's in use here: getme.onl/portfolio/multi-family the tabs should show Colorado, Nevada, Oklahoma, California — Kevin
– Kevin, Commented Aug 25, 2017 at 15:57
How are you iterating over the resulting array? Depending on how it might be of no importance, but do notice that the indices are preserved, Oklahoma's array in the resulting array is 4. — ishegg
– ishegg, Commented Aug 25, 2017 at 15:58

ishegg · Accepted Answer · 2017-08-25 16:04:04Z

3

Your resulting array keeps the original indices, and, depending on how you are iterating over it, you might get unexpected results. Try resetting the indices:

function unique_multidim_array($array, $key) { 
    $temp_array = array(); 
    $i = 0; 
    $key_array = array();           
    foreach( $array as $val ) { 
        if ( ! in_array( $val[$key], $key_array ) ) { 
            $key_array[$i] = $val[$key]; 
            $temp_array[] = $val; // <--- remove the $i
        }
        $i++; 
    } 
    return $temp_array; 
}

Or, as you say, array_values() will help too:

$term_arr = array_values ( unique_multidim_array ( $term_arr, 'name' ) );

answered Aug 25, 2017 at 16:04

ishegg

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Comments

Carlos Alves Jorge · Accepted Answer · 2017-08-25 16:03:08Z

1

PHP already has a function to remove duplicates from an array

array_unique(array)

should do the trick

answered Aug 25, 2017 at 16:03

Carlos Alves Jorge

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3 Comments

Kevin Over a year ago

aye, but it didn't because of the mulitdimensionalness of it

Carlos Alves Jorge Over a year ago

array_map("unserialize", array_unique(array_map("serialize", $array))) could do it...

Paul Laffitte Over a year ago

According to the docs: "Two elements are considered equal if and only if (string) $elem1 === (string) $elem2". So it can't works for multidimensional array The serialize/unserialize option could works but looks dirty.

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