Reorder Array with Duplicate Values in order

Question

What is the best method to preserve the order of an array while placing duplicate values in order.

Here is the array:

Array
(
    [0] => Array
        (
            [location] => 1320 N Street
        )

    [1] => Array
        (
            [location] => 1316 N St

        )

    [2] => Array
        (
            [location] => 1320 N Street
        )

)

I would like to group duplicate locations so it looks like this:

    Array
(
    [0] => Array
        (
            [location] => 1320 N Street
        )

    [1] => Array
        (
            [location] => 1320 N Street

        )

    [2] => Array
        (
            [location] => 1316 N St
        )

)

My initial thought was to loop through the array and perform an array_search on the location key to get the index a duplicate location, then perform a shift to move the location.

Thanks for your time.

Yep, I'd do a loop through the array and put each element into a new array and search for any duplicates in the existing array and cut them out of the original (so that they won't get looped through) and put them into the new. — Blair McMillan
– Blair McMillan, Commented Apr 27, 2012 at 1:45
There's many different sorting option functions for arrays in PHP. Look here: http://php.net/manual/en/array.sorting.php — Norse
– Norse, Commented Apr 27, 2012 at 1:47

Kep · Accepted Answer · 2012-04-27 02:22:42Z

This worked for me:

$arr = array(
        array("location" => "1320 N Street"),
        array("location" => "1320 N St"),
        array("location" => "1320 N Street"),
);

$tmp = array();
$sorted = array();
foreach ($arr as $k => $v)
{
        $s = serialize($v);
        if (!isset($tmp[$s]))
        {
                $tmp[$s] = $k;
                array_push($sorted, $v);
        } else {
                $sorted = array_merge(array_slice($sorted, 0, $tmp[$s]+1), array($v), array_slice($sorted, $tmp[$s]+1));
        }
}

print_r($sorted);

Sample Output:

Array
(
    [0] => Array
        (
            [location] => 1320 N Street
        )

    [1] => Array
        (
            [location] => 1320 N Street
        )

    [2] => Array
        (
            [location] => 1320 N St
        )

)

Edit: Instead of $s = serialize($v); you could also use any key you like, for example $s = $v["location"]; if it's just the location that matters.

Norse · Accepted Answer · 2012-04-27 01:50:01Z

0

You can use array_multisort() to do this.

array_multisort($sub_array[0], SORT_ASC, SORT_STRING,
                $sub_array[1], SORT_NUMERIC, SORT_DESC);

answered Apr 27, 2012 at 1:50

Norse

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1 Comment

Kep Over a year ago

array_multisort wouldn't necessarily preserve the order of non-duplicates, which is that he wants I think.

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