How to sort associative array?

Question

I have associative array. On print_f($array_name), I got this

Array (
        [0] => Array (
            [teamid] => abc
            [distance] => 1.25
        )
        [1] => Array (
            [teamid] => xyz
            [distance] => 0.25
        )
    )

This is that array which I want to sort according to distance. eg, This should be look like this after sorting,

Array (
    [0] => Array (
        [teamid] => xyz
        [distance] => 0.25
    )
    [1] => Array (
        [teamid] => abc
        [distance] => 1.25
    )
)

If anyone know answer then please explain or suggest me link from where I can understand from beginning. Thank You.

check this http://stackoverflow.com/questions/1597736/how-to-sort-an-array-of-associative-arrays-by-value-of-a-given-key-in-php — Devendra Singh Bhandari, Nov 01 '15 at 17:07

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

Here is what you need to do.

$a = array(array( 'teamid' => 'abc', 'distance' => 1.25 ), array( 'teamid' => 'xyz', 'distance' => 0.25 ));

$distance = array();
foreach ($a as $key => $row)
{
    $distance[$key] = $row['distance'];
}
array_multisort($distance, SORT_ASC, $a);

print_r($a);

This outputs

Array
(
    [0] => Array
        (
            [teamid] => xyz
            [distance] => 0.25
        )

    [1] => Array
        (
            [teamid] => abc
            [distance] => 1.25
        )

)

source Example #3 Sorting database results

DEMO

Edit

as per Mike's comment,

here are two answers, one tells that on single array you should use usort(as Mike's answer) and array_multisort is used to compare elements from different arrays (or sub-arrays) at the same time.

in the other answer, as Mike wants some bench marking

usort() is more concise and doesn't require extracting a column array to feed to array_multisort(). (It also does less than array_multisort.)

However, when I repeatedly tested it today on arrays of 20,000 and 10,000 representative data rows, usort() was 7-15x slower than array_multisort() when the column was random values of type int and the column was pre-extracted. That is as one might expect, since for every comparison you're comparing an entire php function call to optimized intrinsic code.

more about bench marking notes, read full answer

I'd be interested in seeing the benchmark between `array_multisort` and `usort` (like I suggest in my separate answer). I think OP would be better off skipping the extra `foreach` loop that's required with `array_multisort` like you've suggested. — Mike Everhart, Nov 01 '15 at 18:11

score 0 · Answer 2 · answered Nov 01 '15 at 17:46

0

$array = array(
    array('teamid' => 'a', 'distance' => 1.25),
    array('teamid' => 'b', 'distance' => 0.25),
    array('teamid' => 'c', 'distance' => 2.5),
    array('teamid' => 'd', 'distance' => 0.75),
);


function cmp($a, $b)
{
    if ($a['distance'] == $b['distance']) return 0;
    return ($a['distance'] < $b['distance']) ? -1 : 1;
}

usort($array, "cmp");

More info: http://php.net/usort

answered Nov 01 '15 at 17:46

Mike Everhart

408
3
10

updating my answer. :) – Mubin Nov 01 '15 at 18:21

How to sort associative array?

2 Answers2