Sorting an array with weights in another array

Question

I get two arrays from

$check = getmxrr ( $domain, $mxhosts, $weight );

I want to get the mxhosts in a third array from lowest to highest weight.

For simplicity let's have simple array names and values:

$s = array('slowest','fast','very slow', 'slow','very fast', 'fastest');
$n = array( 40,       10,    30,          20,    5,           0       );

Now, with this code, I can get the ordered array I'm looking for:

$o = array_combine($n, $s);
ksort($o);

But, if there are elements with the same weight, only the last element with the repeated weight would appear in the ordered array.

Is there any similar (low footprint) solution without this issue?

Illustrative cases follow.

Weight values are unique. Output is OK:

[0] => fastest
[5] => very fast
[10] => fast
[20] => slow
[30] => very slow
[40] => slowest

We have same-weight elements. Output is NOT OK (fast is gone):

$n = array( 40,       10,    30,         10,       20,    5,           0       );
$s = array('slowest','fast','very slow','fast2', 'slow','very fast', 'fastest');

[0] => fastest
[5] => very fast
[10] => fast2
[20] => slow
[30] => very slow
[40] => slowest

it makes a new array $o with keys from $s and value from $n by order $o[$n[0]] = $s[0] — gmaliar
– gmaliar, Commented May 31, 2012 at 11:45
@CoDeaDDict it's a native function: php.net/manual/en/function.array-combine.php — Majid Fouladpour
– Majid Fouladpour, Commented May 31, 2012 at 11:45
I'm trying to understand if two elements has the same weight ksort won't sort the array by the keys correctly? Can you show how it sorts it? — gmaliar
– gmaliar, Commented May 31, 2012 at 11:46
and how would you like the array as well ;-), maybe natsort() would do the trick ... depends on what you want exactly ... — gmaliar
– gmaliar, Commented May 31, 2012 at 11:47

yenta · Accepted Answer · 2012-05-31 12:10:39Z

2

Since you believe the host names are unique, switch the order of the combine

$n = array( 40,       10,    30,         10,       20,    5,           0       );
$s = array('slowest','fast','very slow','fast2', 'slow','very fast', 'fastest');
$o = array_combine($s, $n);

and use asort to sort on values while maintaining keys

asort($o);

than your sorted host names are in array_keys

var_dump(array_keys($o));
array(7) {
  [0]=>
  string(7) "fastest"
  [1]=>
  string(9) "very fast"
  [2]=>
  string(5) "fast2"
  [3]=>
  string(4) "fast"
  [4]=>
  string(4) "slow"
  [5]=>
  string(9) "very slow"
  [6]=>
  string(7) "slowest"
}

var_dump($o);
array(7) {
  ["fastest"]=>
  int(0)
  ["very fast"]=>
  int(5)
  ["fast2"]=>
  int(10)
  ["fast"]=>
  int(10)
  ["slow"]=>
  int(20)
  ["very slow"]=>
  int(30)
  ["slowest"]=>
  int(40)
}

answered May 31, 2012 at 12:10

yenta

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Comments

flowfree · Accepted Answer · 2012-05-31 12:14:55Z

1

You can do this:

$s = array('slowest','fast', 'slow', 'fastest', 'slow 2');
$n = array( 40, 10, 20, 0, 20);

$res = array();
foreach ($n as $k => $v) {
    $res[$v] .= count($res[$v]) ? ",{$s[$k]}" : $s[$k];
}

ksort($res);
$res = explode(',', implode(',', $res));

print_r($res);
/*
Array
(
    [0] => fastest
    [1] => fast
    [2] => slow
    [3] => slow 2
    [4] => slowest
)
*/

edited May 31, 2012 at 12:14

answered May 31, 2012 at 11:52

flowfree

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2 Comments

Majid Fouladpour Over a year ago

The value of wights are not important; only they need to be in the correct order. So, all I want in the above case is ('fastest', 'fast', 'slow', 'slow 2', 'slowest')

Majid Fouladpour Over a year ago

Thank you for the effort. This code does get the job done, but generates many notices.

gmaliar · Accepted Answer · 2012-05-31 11:59:13Z

0

Try this

function cmp($a, $b)
{
    if ($a > $b)
        return 1;
    elseif ($b > $a)
        return -1;
    else
       return 0;
}

uksort($array, 'cmp');

answered May 31, 2012 at 11:59

gmaliar

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1 Comment

Majid Fouladpour Over a year ago

Is $array in the above, the $weight array? If so, what effect would that have on $mxhosts array? -- $mxhosts is what I need sorted as per values in $weight though

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