Question

How do I sort array that has highest point from 15.00 key?

I have an array look like this:

Array
(

    [9] => Array
        (
            [15.00] => 3.0
            [20.00] => 8.0
            [25.00] => 10.5
        )

    [2] => Array
        (
            [15.00] => 2.0
            [20.00] => 5.0
            [25.00] => 2.5
        )


    [4] => Array
        (
            [15.00] => 6.0
            [25.00] => 4.0
            [30.00] => 6.0
        )
)

In order it should be: 4, 9 and 2

Answer 1

PHP has usort, a function enabling you to sort via a user-provided comparison function. There’s also uasort that maintains index association.

Here’s an example:

<?php
$array = Array(
  9 => Array(
            15.00 => 3.0,
            20.00 => 8.0,
            25.00 => 10.5
  ),
  2 => Array(
            15.00 => 2.0,
            20.00 => 5.0,
            25.00 => 2.5
  ),
  4 => Array(
            15.00 => 6.0,
            25.00 => 4.0,
            30.00 => 6.0
  )
);

function my_func($a, $b) {
   if ($a[15.00] == $b[15.00])
      return 0;
   return ($a[15.00] < $b[15.00]) ? 1 : -1; // backwards sorting
}

uasort($array, my_func);
var_dump($array);
?>

And here’s it working.

Hope this helps.