Sort a 2d array by values in a column related to a flat priority array

Question

I have an array with IDs that looks like

 $order_ids = array(8,9,10,4,7);

and another multidimensional array that looks like

$multiarray = [
    [4, 23, 1],
    [9, 66, 4],
    [8, 17, 3],
];

I tried

 $keys = array_flip($order_ids);

 usort($multiarray, function($a, $b) use ($keys)
 {
     return $keys[$a] - $keys[$b[0];
 });

The order_ids of the 2nd array correspond to the values in the first array. What I need to do is sort the 2nd array by the order_ids in the order they are in the 1st array.

What ahve you tried and where were you stuck? There are plenty of examples for similar problems both on and off the site, they should've gotten you at least halfway to a solution. — El_Vanja
– El_Vanja, Commented Jun 4, 2021 at 9:04
please show us your best attempt at solving your issue, you might be closer than you think! Suggested reading How to Ask. — berend
– berend, Commented Jun 4, 2021 at 9:11
You use ['id'], but the array you're trying to sort is not associative. You have marked the 0 index as the one with the order id, so you should try [0] instead. P.S. This should be giving you Undefined index notices. — El_Vanja
– El_Vanja, Commented Jun 4, 2021 at 9:19

jibsteroos · Accepted Answer · 2021-06-04 09:22:33Z

1

You could cycle through the records in $arr and store them in the order set by $order_ids - result in $newArr:

<?php
$order_ids = array(8,9,10,4,7);

$arr = [
    [4, 23, 1],
    [9, 66, 4],
    [8, 17, 3],
];

foreach($order_ids as $id) {
    foreach($arr as $record) {
        if($record[0] == $id) {
            $newArr[] = $record;
            break;
        }
    }
}

demo

answered Jun 4, 2021 at 9:22

jibsteroos

1,4012 gold badges9 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

mickmackusa · Accepted Answer · 2025-01-31 10:35:21Z

0

Reference the flipped lookup array to compare values by their priority value. Demo

$map = array_flip($order_ids);

usort($array, fn($a, $b) => $map[$a[0]] <=> $map[$b[0]]);

var_export($array);

answered Jan 31 at 10:35

mickmackusa♦

49.2k13 gold badges98 silver badges165 bronze badges

Collectives™ on Stack Overflow

Sort a 2d array by values in a column related to a flat priority array

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related