php custom sort function numeric

Question

I am having a custom sort-funktion wich I use with usort:

function cmp($wert_a, $wert_b) {
$a = $wert_a["name"];
$b = $wert_b["name"];

if ($a == $b) {
   return 0;
}

return ($a < $b) ? -1 : +1; 
}

Now when I am having a array like this:5a,10b,6c,HR9,44x it sorts it into 10b,44x,5a,6c,HR9.

I would like to have it sorted like 5a,6c,10b,44x,HR9

How can this be achieved?

Edit: One thing i didn't really mention (I did in code but not in text) is that it is a multi-dimensional array like this:

$array[0]["name"] = "5b";
$array[0]["..."] = "other values";
$array[1]["name"] = "10a";
$array[1]["..."] = "other values";

Using natsort and friends i cannot sort it like this.

IMHO its often expensive, usually pointless and sometimes even dangerous to spend time on micro-optimization before the code has the correct behavior. — Andre Bossard
– Andre Bossard, Commented Sep 9, 2012 at 17:42

rationalboss · Accepted Answer · 2012-09-09 18:17:15Z

5

I suggest that you just use natsort(). It behaves the same way as what you are trying to create.

To sort mult-dimensional arrays, refer to this: http://www.php.net/manual/en/function.array-multisort.php#61976

function array_key_multi_sort($arr, $l , $f='strnatcasecmp')
{
    usort($arr, create_function('$a, $b', "return $f(\$a['$l'], \$b['$l']);"));
    return($arr);
}

edited Sep 9, 2012 at 18:17

answered Sep 9, 2012 at 17:38

rationalboss

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1 Comment

Zulakis Over a year ago

Have a look at my edit please: In my case it is a multi-dimensional array. How can i use natsort with it?

Florian Eckerstorfer · Accepted Answer · 2012-09-09 18:23:08Z

1

If you want to sort characters in their natural order (a is before H) you can use natcasesort. Consider the following array:

$array = array('5a', '10b', '6c', 'HR9', '44x', 'a9');

Using natsort:

Array
(
    [0] => 5a
    [2] => 6c
    [1] => 10b
    [4] => 44x
    [3] => HR9
    [5] => a9
)

Using natcasesort:

Array
(
    [0] => 5a
    [2] => 6c
    [1] => 10b
    [4] => 44x
    [5] => a9
    [3] => HR9
)

Edit: You can see in the output, that the indices stay the same even after the sort. Thus to sort a associative array you can create a one-dimensional copy and access the associative array with its indices. Don't forget to use foreach and not for when iterating through the sorted array.

edited Sep 9, 2012 at 18:23

answered Sep 9, 2012 at 18:00

Florian Eckerstorfer

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2 Comments

Zulakis Over a year ago

Have a look at my edit please: In my case it is a multi-dimensional array. How can i use natsort with it?

Florian Eckerstorfer Over a year ago

I would recommend to use a one-dimensional array for sorting since it is faster and you don't have to duplicate PHPs functionality. This is especially true if your array is very large. Please see my edit for more information

Douglas.Sesar · Accepted Answer · 2012-09-09 18:23:49Z

0

Well for every item in the array except HR9, the natsort() function in php would handle the sorting pretty well. It disregards non-numeric characters and sorts by the number characters as if they were numeric.

here is the documentation on natsort(). http://us.php.net/natsort

$array = array(5a,10b,6c,HR9,44x);

natsort($array);

the new order should now be:

5a,6c,HR9,10b,44x

after this you could use your sorting function and only sort if the first character of one of the strings is non-numeric

In regards to your multi-dimensional array:

$temp_array = array();
foreach($array as $key => $value):

$temp_array[$key] = $value['name'];


endforeach;

natsort($temp_array);

this will give you an ordered associative array with the keys being the original array's element number and the values being the 'name'

you could

edited Sep 9, 2012 at 18:23

answered Sep 9, 2012 at 17:52

Douglas.Sesar

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1 Comment

Zulakis Over a year ago

Have a look at my edit please: In my case it is a multi-dimensional array. How can i use natsort with it?

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