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natsort

(PHP 4, PHP 5)

natsortSortiert ein Array in "natürlicher Reihenfolge"

Beschreibung

bool natsort ( array &$array )

Diese Funktion implementiert einen Sortieralgorithmus, welcher alphanumerische Zeichenketten reiht, wie es auch ein Mensch tun würde, wobei Sie die Schlüssel-Wert-Zuordnung beibehält. Das wird als "natürliche Reihenfolge" bezeichnet. würde. Hier ein Beispiel für den Unterschied zwischen diesem und dem normalen Sortieralgorithmus für Strings eines Computers (verwendet in sort()):

Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.

Beispiel #1 natsort()

<?php
$array1 
$array2 = array("img12.png""img10.png""img2.png""img1.png");
sort ($array1);
echo 
"Standardsortierung\n";
print_r ($array1);

natsort ($array2);
echo 
"\nSortieren mit natürlicher Reihenfolge\n";
print_r ($array2);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Standardsortierung
Array
(
    [0] => img1.png
    [1] => img10.png
    [2] => img12.png
    [3] => img2.png
)

Sortieren mit natürlicher Reihenfolge
Array
(
    [3] => img1.png
    [2] => img2.png
    [1] => img10.png
    [0] => img12.png
)

Detailliertere Informationen finden Sie auf Martin Pool's » Natural Order String Comparison Seite.

Siehe auch natcasesort(), strnatcmp() und strnatcasecmp().

add a note add a note

User Contributed Notes 18 notes

up
9
Johan GENNESSON (php at genjo dot fr)
3 years ago
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
up
4
h3
8 years ago
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'
up
5
flash at minet dot net
11 years ago
About the reverse natsort.. Maybe simpler to do :

function strrnatcmp ($a, $b) {
    return strnatcmp ($b, $a);
}
up
4
xlab AT adaptiveNOSPAMarts DOT net
10 years ago
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.
up
2
Christoph
4 years ago
Note:

The natsort function will sort depending on the operating system, but not depending on either Linux or Windows-based systems

There's a difference when sorting an array which is generated from the filesystem:
Array(
    [0] => ./system/kernel/js/01_ui.core.js
    [1] => ./system/kernel/js/00_jquery-1.3.2.js
    [2] => ./system/kernel/js/02_my.desktop.js
)

natsort($array) will result in two different ways:

Case 1: (Debian)
Array(
    [1] => ./system/kernel/js/00_jquery-1.3.2.js
    [0] => ./system/kernel/js/01_ui.core.js
    [2] => ./system/kernel/js/02_my.desktop.js
)

Case 2: (Debian Kernel, but Ubuntu shadowed php-Version)
Array(
    [0] => ./system/kernel/js/01_ui.core.js
    [2] => ./system/kernel/js/02_my.desktop.js
    [1] => ./system/kernel/js/00_jquery-1.3.2.js
)

...so make sure you've named the files beginning with 01, then it works fine.
up
1
wyvern at greywyvern dot com
5 years ago
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");
?>
up
0
ale152
5 years ago
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 )
up
0
AJenbo
5 years ago
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
)
*/
up
0
lacent at gmail dot com
7 years ago
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;
    }
up
0
@gmail bereikme
7 years ago
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
up
0
Anonymous
8 years ago
The last comment should have been posted in doc about (r)sort( ). Indeed, and unfortunately, ORDER BY *does not* perform natural ordering. So, sometimes we *must* do a SQL request followed by natsort( ).
up
0
lil at thedreamersmaze dot spam-me-not dot org
8 years ago
There's one little thing missing in this useful bit of code posted by mbirth at webwriters dot de:

<?php

function 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;
}

?>
up
0
natcasesort.too
9 years ago
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!
up
0
phpnet at moritz-abraham dot de
9 years ago
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,test3
or
0,2,1,4,5,3.

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;
}
?>
up
0
mbirth at webwriters dot de
10 years ago
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.

<?php

function 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;
}

?>
up
0
rasmus at flajm dot com
10 years ago
To make a reverse function, you can simply:

function rnatsort(&$a){
    natsort($a);
    $a = array_reverse($a, true);
}
up
0
justin at redwiredesign dot com
11 years ago
One of the things I've needed to do lately is apply natural sorting to a complex array, e.g.:

Array
(
    [0] => Array
        (
            [ID] = 4
            [name] = Fred
        )
       
    [1] => Array
        (
            [ID] = 6
            [name] = Bob
        )
)

where I want to sort the parent array by the child's name. I couldn't see a way of doing this using array_walk, so I've written a simple function to do it. Hopefully someone will find this useful:

/**
* @return Returns the array sorted as required
* @param $aryData Array containing data to sort
* @param $strIndex Name of column to use as an index
* @param $strSortBy Column to sort the array by
* @param $strSortType String containing either asc or desc [default to asc]
* @desc Naturally sorts an array using by the column $strSortBy
*/
function array_natsort($aryData, $strIndex, $strSortBy, $strSortType=false)
{
    //    if the parameters are invalid
    if (!is_array($aryData) || !$strIndex || !$strSortBy)
        //    return the array
        return $aryData;
       
    //    create our temporary arrays
    $arySort = $aryResult = array();
   
    //    loop through the array
    foreach ($aryData as $aryRow)
        //    set up the value in the array
        $arySort[$aryRow[$strIndex]] = $aryRow[$strSortBy];
       
    //    apply the natural sort
    natsort($arySort);

    //    if the sort type is descending
    if ($strSortType=="desc")
        //    reverse the array
        arsort($arySort);
       
    //    loop through the sorted and original data
    foreach ($arySort as $arySortKey => $arySorted)
        foreach ($aryData as $aryOriginal)
            //    if the key matches
            if ($aryOriginal[$strIndex]==$arySortKey)
                //    add it to the output array
                array_push($aryResult, $aryOriginal);

    //    return the return
    return $aryResult;
}
up
-1
anonymous at coward dot net
11 years ago
Reverse Natsort:

  function rnatsort($a, $b) {
    return -1 * strnatcmp($a, $b);
  }

  usort($arr, "rnatsort");
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