natsort

There's no need to include your own API code to natsort an associative array by key.  PHP's in-built functions (other than natsort) can do the job just fine:<?php  uksort($myArray, "strnatcmp");?>

Be careful of the new behaviour in 5.2.10 version.See the following sample:<?php$array = array('1 bis', '10 ter', '0 PHP', '0', '01', '01 Ver', '0 ', '1 ', '1');natsort($array);echo '<pre>';print_r($array);echo '</pre>';?>5.2.6-1 will output:Array(    [3] => 0    [6] => 0     [2] => 0 OP    [4] => 01    [5] => 01 Ver    [8] => 1    [7] => 1     [0] => 1 bis    [1] => 10 ter)5.2.10 will output:Array(    [6] => 0     [3] => 0    [8] => 1    [4] => 01    [7] => 1     [5] => 01 Ver    [0] => 1 bis    [1] => 10 ter    [2] => 0 OP)Greetings

About the reverse natsort.. Maybe simpler to do :function strrnatcmp ($a, $b) {    return strnatcmp ($b, $a);}

Under limited testing, natsort() appears to work well for IP addresses. For my needs, it is far less code than the ip2long()/long2ip() conversion I was using before.

To make a reverse function, you can simply:function rnatsort(&$a){    natsort($a);    $a = array_reverse($a, true);}

For those who want to natsort a 2d-array on the first element of each sub-array, the following few lines should do the job.<?phpfunction natsort2d(&$aryInput) {  $aryTemp = $aryOut = array();  foreach ($aryInput as $key=>$value) {    reset($value);    $aryTemp[$key]=current($value);  }  natsort($aryTemp);  foreach ($aryTemp as $key=>$value) {    $aryOut[] = $aryInput[$key];  }  $aryInput = $aryOut;}?>

Reverse Natsort:  function rnatsort($a, $b) {    return -1 * strnatcmp($a, $b);  }  usort($arr, "rnatsort");

Note: negatives number.<?php$a = array(-5,-2,3,9);natsort($a);print_r($a);?>Will output:Array ( [1] => -2 [0] => -5 [2] => 3 [3] => 9 )

I got caught out through naive use of this feature - attempting to sort a list of image filenames from a digital camera, where the filenames are leading zero padded (e.g. DSCF0120.jpg) , will not sort correctly.Maybe the example could be modified to exhibit this behaviour (e.g. set array to -img0120.jpg','IMG0.png', 'img0012.png', 'img10.png', 'img2.png', 'img1.png', 'IMG3.png)If the example hadn't used images I would have coded it correctly first time around!

additional to the code posted by justin at redwiredesign dot com (which I found very usefull) here is a function that sorts complex arrays like this:<?$array['test0'] = array('main' =>  'a', 'sub' => 'a');$array['test2'] = array('main' =>  'a', 'sub' => 'b');$array['test3'] = array('main' =>  'b', 'sub' => 'c');$array['test1'] = array('main' =>  'a', 'sub' => 'c');$array['test4'] = array('main' =>  'b', 'sub' => 'a');$array['test5'] = array('main' =>  'b', 'sub' => 'b');?>or<?$array[0] = array('main' =>  1, 'sub' => 1);$array[2] = array('main' =>  1, 'sub' => 2);$array[3] = array('main' =>  2, 'sub' => 3);$array[1] = array('main' =>  1, 'sub' => 3);$array[4] = array('main' =>  2, 'sub' => 1);$array[5] = array('main' =>  2, 'sub' => 2);?>on one or more columns.the code<? $array = array_natsort_list($array,'main','sub'); ?>will result in $array being sortet like this:test0,test2,test1,test4,test5,test3or0,2,1,4,5,3.you may even submit more values to the function as it uses a variable parameter list. the function starts sorting on the last and the goes on until the first sorting column is reached.to me it was very usefull for sorting a menu having submenus and even sub-submenus.i hope it might help you too.here is the function:<?function array_natsort_list($array) {    // for all arguments without the first starting at end of list    for ($i=func_num_args();$i>1;$i--) {        // get column to sort by        $sort_by = func_get_arg($i-1);        // clear arrays        $new_array = array();        $temporary_array = array();        // walk through original array        foreach($array as $original_key => $original_value) {            // and save only values            $temporary_array[] = $original_value[$sort_by];        }        // sort array on values        natsort($temporary_array);        // delete double values        $temporary_array = array_unique($temporary_array);        // walk through temporary array        foreach($temporary_array as $temporary_value) {            // walk through original array            foreach($array as $original_key => $original_value) {                // and search for entries having the right value                if($temporary_value == $original_value[$sort_by]) {                    // save in new array                    $new_array[$original_key] = $original_value;                }            }        }        // update original array        $array = $new_array;    }    return $array;}?>

This made me waste a lot of my precious youth ... natsort() is buggy if all numbers don't have the same number of decimal places.(php 5.6.4-4ubuntu6.2)<?php $different_decimal_places_in_values = array('D'=>'13.59', '14.6' => '14.6', 'C-' => '14.19'); natsort($a); var_dump($a);/*echoesarray(3) {  'D' =>  string(5) "13.59"  '14.6' =>  string(4) "14.6" <----------- badly ordered  'C-' =>  string(5) "14.19"}*/?>While this <?php $same_num_decimal_places_in_values = array('D'=>'13.59', '14.6' => '14.60', 'C-' => '14.19'); natsort($a); var_dump($a);/*echoes array(3) {  'D' =>  string(5) "13.59"  'C-' =>  string(5) "14.19"  '14.6' =>  string(5) "14.60" <--------- that is the correct position}*/?>

there is another rnatsort function lower on the page, but it didn't work in the context i needed it in. reasoning for this:sorting naturally via the keys of an array, but needing to reverse the order.    function rnatsort ( &$array = array() )     {        $keys    = array_keys($array);        natsort($keys);        $total    = count($keys) - 1;        $temp1    = array();        $temp2     = array();        // assigning original keys to an array with a backwards set of keys, to use in krsort();        foreach ( $keys as $key )        {            $temp1[$total] = $key;            --$total;        }                ksort($temp1);        // setting the new array, with the order from the krsort() and the values of original array.        foreach ( $temp1 as $key )         {            $temp2[$key] = $array[$key];        }        $array = $temp2;    }

This function can be very usefull, but in some cases, like if you want to sort a MySQL query result, it's important to keep in mind that MySQL as built'in sorting functions which are way faster than resorting the result using a complex php algorythm, especially with large arrays.ex; 'SELECT * FROM `table` ORDER BY columnName ASC, columnName2 DESC'

$array1 = $array2 = array('IMG0.png', 'img12.png', 'img10.png', 'img2.png', 'img1.png', 'IMG3.png');natsort($array1);echo "\n natsort(); \n";print_r($array1);sort($array2, SORT_NATURAL);echo "\n sort() with  SORT_NATURAL Option\n";print_r($array2);Ouput:natsort();Array(    [0] => IMG0.png    [5] => IMG3.png    [4] => img1.png    [3] => img2.png    [2] => img10.png    [1] => img12.png)sort() with  SORT_NATURAL OptionArray(    [0] => IMG0.png    [1] => IMG3.png    [2] => img1.png    [3] => img2.png    [4] => img10.png    [5] => img12.png)as we can see it's  the same values but not the same keys, and also it's same for sort($array1, SORT_NATURAL | SORT_FLAG_CASE); and natcasesort($array2)

As noted in other notes, natsort() does _not_ always return the expected sort order. It seems especially buggy when decimals or 0 padding is used. I've filed this bug report on the issue:https://bugs.php.net/bug.php?id=74672

To naturally sort by array key, the uksort function can be used.<?phpecho "Sort by keys\n";$smoothie = array('orange' => 1, 'apple' => 1, 'yogurt' => 4, 'banana' => 4);print_r($smoothie);uksort( $smoothie, 'strnatcmp');print_r($smoothie)?>Output:Sort by keysArray(    [orange] => 1    [apple]  => 1    [yogurt] => 4    [banana] => 4)Array(    [apple]  => 1    [banana] => 4    [orange] => 1    [yogurt] => 4)See http://php.net/manual/en/function.uksort.php for more information about uksort and http://php.net/strnatcmp for usage of strnatcmp.

Here's a handy function to sort an array on 1 or more columns using natural sort:<?php// Example: $records = columnSort($records, array('name', 'asc', 'addres', 'desc', 'city', 'asc'));$globalMultisortVar = array();function columnSort($recs, $cols) {    global $globalMultisortVar;    $globalMultisortVar = $cols;    usort($recs, 'multiStrnatcmp');    return($recs);}function multiStrnatcmp($a, $b) {    global $globalMultisortVar;    $cols = $globalMultisortVar;    $i = 0;    $result = 0;    while ($result == 0 && $i < count($cols)) {        $result = ($cols[$i + 1] == 'desc' ? strnatcmp($b[$cols[$i]], $a[$cols[$i]]) : $result = strnatcmp($a[$cols[$i]], $b[$cols[$i]]));        $i+=2;    }    return $result;}?>Greetings,  - John

There's one little thing missing in this useful bit of code posted by mbirth at webwriters dot de:<?phpfunction natsort2d(&$aryInput) {  $aryTemp = $aryOut = array();  foreach ($aryInput as $key=>$value) {   reset($value);   $aryTemp[$key]=current($value);  }  natsort($aryTemp);  foreach ($aryTemp as $key=>$value) {   $aryOut[$key] = $aryInput[$key]; // --------^^^^ add this if you want your keys preserved!  }  $aryInput = $aryOut;}?>

natsort might not act like you would expect with zero padding, heres a quick sample.

<?php
$array = array('09', '8', '10', '009', '011');
natsort($array);
?>
/*
Array
(
    [3] => 009
    [4] => 011
    [0] => 09
    [1] => 8
    [2] => 10
)
*/