natsort

(PHP 4, PHP 5, PHP 7)

natsortOrdena um array utilizando o algoritmo da "ordem natural"

Descrição

natsort ( array &$array ) : bool

Essa função é um implementação do algoritmo que ordena strings alfanuméricas da forma como um ser humano faria mantendo associação de chave/valor. Isso é chamado de "ordenação natural". Um exemplo da diferença entre esse algoritmo e o algoritmo com o qual o computador classifica strings (usado em sort()) pode ser visto abaixo:

Parâmetros

array

O array de entrada.

Valor Retornado

Retorna TRUE em caso de sucesso ou FALSE em caso de falha.

Exemplos

Exemplo #1 Exemplo da natsort()

$array1 = $array2 = array("img12.png", "img10.png", "img2.png", "img1.png");

sort($array1);
echo "Classificação normal\n";
print_r($array1);

natsort($array2);
echo "\nClassificação da \"ordem natural\"\n";
print_r($array2);

O exemplo acima irá imprimir:

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

Classificação da "ordem natural"
Array
(
    [3] => img1.png
    [2] => img2.png
    [1] => img10.png
    [0] => img12.png
)

Para mais informações veja: Martin Pool's » Natural Order String Comparison page.

Veja Também

  • natcasesort() - Ordena um array utilizando o algoritmo da "ordem natural" sem diferenciar maiúsculas e minúsculas
  • strnatcmp() - Comparação de strings usando o algoritmo "natural order"
  • strnatcasecmp() - Comparação de strings sem diferenciar maiúsculas/minúsculas usando o algoritmo "natural order"

add a note add a note

User Contributed Notes 19 notes

up
28
wyvern at greywyvern dot com
10 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
10
flash at minet dot net
16 years ago
About the reverse natsort.. Maybe simpler to do :

function strrnatcmp ($a, $b) {
    return strnatcmp ($b, $a);
}
up
13
Johan GENNESSON (php at genjo dot fr)
9 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
3
bb7b5b9 at gmail dot com
3 years ago
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);

/*echoes
array(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
}
*/

?>
up
8
xlab AT adaptiveNOSPAMarts DOT net
15 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
4
mbirth at webwriters dot de
15 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
4
rasmus at flajm dot com
15 years ago
To make a reverse function, you can simply:

function rnatsort(&$a){
    natsort($a);
    $a = array_reverse($a, true);
}
up
3
anonymous at coward dot net
16 years ago
Reverse Natsort:

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

  usort($arr, "rnatsort");
up
2
ale152
10 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
2
natcasesort.too
14 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
2
phpnet at moritz-abraham dot de
15 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
2
h3
13 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
1
@gmail bereikme
13 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
1
dotancohen splat gmail spot com
2 years ago
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
up
0
Malek Mohamed
1 year ago
$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 Option
Array
(
    [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)
up
0
mvs dot php at gmail dot com
4 years ago
To naturally sort by array key, the uksort function can be used.

<?php

echo "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 keys
Array
(
    [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.
up
0
lacent at gmail dot com
12 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
-1
lil at thedreamersmaze dot spam-me-not dot org
13 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
-2
AJenbo
10 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
)
*/
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