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I have an array like this:

array(
    'sortBy' => array(0 => 3,   1 => 2,   2 => 1),
    'other'  => array(0 => 'x', 1 => 'y', 2 => 'z'),
    'xxx'    => array(0 => 3,   1 => 2,   2 => 1),
    ...
)

How can I sort contents of subarray other by values in sortBy ? There's unlimited amount of other subarrays inside that one array, but the keys inside these subarrays are always same(e.g. in sortBy, other, xxx the values of key 0 must all be sorted together)

Sorted array would look like this:

array(
    'sortBy' => array(0 => 1,   1 => 2,   2 => 3),
    'other'  => array(0 => 'z', 1 => 'y', 2 => 'x'),
    'xxx'    => array(0 => 1,   1 => 2,   3 => 3)
)
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1 Answer

up vote 1 down vote accepted

You could use array_multisort() to good effect.

$array = array(
    'sortBy' => array(3,   2,   1),
    'other'  => array('x', 'y', 'z'),
    'xxx'    => array(3,   2,   1),
);

array_multisort($array['sortBy'], SORT_NUMERIC, $array['other'], $array['xxx']);

var_export($array);

The above example prints the following:

array (
  'sortBy' => 
  array (
    0 => 1,
    1 => 2,
    2 => 3,
  ),
  'other' => 
  array (
    0 => 'z',
    1 => 'y',
    2 => 'x',
  ),
  'xxx' => 
  array (
    0 => 1,
    1 => 2,
    2 => 3,
  ),
)

Edit

Since you decided the array's keys could be anything (other than the one definite key: sortBy), then array_multisort() can still be used albeit called with a more dynamic list of arguments.

$array = array( … );

$args = array(&$array['sortBy'], SORT_NUMERIC);
foreach ($array as $key => $value) {
    if ($key !== 'sortBy') {
        $args[] = &$array[$key];
    }
}
call_user_func_array('array_multisort', $args);
unset($args);

var_export($array);
share|improve this answer
I cannot call this function like that, because I don't know all the possible keys, only the sortBy key is known, all other keys are random. – Dalius Apr 16 at 18:01
Then use call_user_func_array() with an appropriate array of arguments (see edit). – salathe Apr 16 at 18:11
Works without "if ($key !== 'sortBy')", but I'll add it just to be safe :) – Dalius Apr 16 at 18:16
Yes, it would work but it would be doing extra sorting that is not needed. – salathe Apr 16 at 19:01

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