sort a multidimensional array using array_multisort

Question

I have this array

Array
(
    [0] => Array
        (
            [brand] => blah blah
            [location] => blah blah
            [address] => blah blah
            [city] => blah blah
            [state] => CA
            [zip] => 90210
            [country] => USA
            [phone] => 555-1212
            [long] => -111
            [lat] => 34
            [distance] => 3.08
        )
    [1] => Array
        (
            [brand] => blah blah
            [location] => blah blah
            [address] => blah blah
            [city] => blah blah
            [state] => CA
            [zip] => 90210
            [country] => USA
            [phone] => 555-1212
            [long] => -111
            [lat] => 34
            [distance] => 5
        )
.
.
.

}

I want to be able to sort the arrays in the hash by distance.

Answer 1

You need to extract all the distances first, then pass both the distance and the data to the function. As shown in example 3 in the array_multisort documentation.

foreach ($data as $key => $row) {
    $distance[$key] = $row['distance'];
}

array_multisort($distance, SORT_ASC, $data);

This assumes you want the shortest distances first, otherwise change the SORT_ASC to SORT_DESC

Answer 2

If you want to avoid the looping you can use the array_column function to achieve your target. For Example,

You want to sort below array with distance sort

$arr = array( 
  0 => array( 'lat' => 34, 'distance' => 332.08 ),
  1 => array( 'lat' => 34, 'distance' => 5 ),
  2 => array( 'lat' => 34, 'distance' => 34 )
);

Using below single line your array will be sort by distance

array_multisort( array_column( $arr, 'distance' ), SORT_ASC, SORT_NUMERIC, $arr );

Now, $arr contain with sorted array by distance