PHP: array_multisort

Описание

bool array_multisort ( array ar1 [, mixed arg [, mixed ... [, array ...]]] )

Функция array_multisort() может быть использована для сортировки сразу нескольких массивов или одного многомерного массива в соответствии с одной или несколькими размерностями. Эта функция сохраняет соответствие между ключами и соответствующими им значениями.

Входные массивы рассматриваются как столбцы таблицы, которую нужно отсортировать по строкам - такой подход напоминает поведение выражения SQL ORDER BY. Первый массив имеет проиоритет в процессе сортировки.

Структура аргументов этой функции немного необычна, но удобна. Первым аргументом должен быть массив. Последующие аргументы могут быть как массивами, так и значениями, определяющими порядок сортировки, приведенными в нижеследующем списке.

Значения, определяющие порядок сортировки:

SORT_ASC - сортировать в возрастающем порядке
SORT_DESC - сортировать в убывающем порядке

Sorting type flags:

SORT_REGULAR - сравнивать элементы обычным образом
SORT_NUMERIC - сравнивать элементы, как если бы они были числами
SORT_STRING - сравнивать элементы, как если бы они были строками

Недопустимым является указание двух флагов сортировки одинакового типа после каждого массива. Флаги сортировки, переданные после аргумента массив, применяются только к этому аргументу - перед тем, как функция начнет обрабатывать следующий массив, эти флаги снова принимают значения по умолчаниюt SORT_ASC и SORT_REGULAR.

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.

Пример 1. Сортировка нескольких массивов

$ar1 = array ("10", 100, 100, "a"); $ar2 = array (1, 3, "2", 1); array_multisort ($ar1, $ar2);

В вышеприведенном примере, после того, как будет осуществлена сортировка, первый массив будет содержать 10, "a", 100, 100. Второй - 1, 1, "2", 3. Элементы второго массива, соответствующие идентичным элементам первого (100 и 100), также будут отсортированы.

Пример 2. Сортировка многомерного массива

$ar = array (array ("10", 100, 100, "a"), array (1, 3, "2", 1)); array_multisort ($ar[0], SORT_ASC, SORT_STRING, $ar[1], SORT_NUMERIC, SORT_DESC);

В вышеприведенном примере, после сортировки, первый массив будет содержать 10, 100, 100, "a" (его элементы были отсортированы в возрастающем порядке так, как если бы они были строками), а второй массив будет содержать 1, 3, "2", 1 (элементы отсортированы как числа, в порядке убывания).

array_multisort

Cesar Sirvent
17-May-2006 09:43


There is a problem with array_multisort in languages other than English.

For special chars, as A with accent (Á), the sorting does not correspond to what might expect from a MySQL SELECT with ORDER BY.



For example



<?php

 

       foreach ($students as $key => $row){

          $surname[$key] = $row['surname'];

       }

       array_multisort($surname, SORT_ASC, $students);

?>



will sort the array in this way: ABADIA, ALVAREZ, BUÑUEL, ZUBIETA, ÁLVARES



while a MySQL SELECT with ORDER BY nombre ASC will yield



ABADIA, ÁLVARES, ALVEREZ, BUÑUEL, ZUBIETA



as A and Á are considered two different representations of the same letter.

scott - evolove - net - work it out
22-Mar-2006 07:51


A very simple way to sort an array of associative arrays by some value is to use usort.



I needed to sort an array of 20 data structures by their 'distance' value:



Array

(

    [0] => Array

        (

            [blahblah] => blahblah

            [distance] => 6

        )



    [1] => Array

        (

          you get the idea....



Here's the code:



--------------------

usort($results, "distributor_compare");



/**

 * usort callback

 */

function distributor_compare($a, $b) {

    $adist = intval($a['distance']);

    $bdist = intval($b['distance']);

    

    if ($adist == $bdist) {

     return 0;

     }

     return ($adist < $bdist) ? -1 : 1;    

}

--------------------

peter dot graham at tcat dot ac dot uk
16-Feb-2006 07:16


Many thanks to �AlberT at SuperAlberT dot it� for his useful and elegant function. I have made some small alterations so it doesn�t use pass-by-reference as this throws up warnings in newer versions of php4.



<?php



function array_key_multi_sort($arr, $l , $f='strnatcasecmp')

{

    usort($arr, create_function('$a, $b', "return $f(\$a['$l'], \$b['$l']);"));

    return($arr);

}



?>

mail at theopensource dot com
31-Jan-2006 11:34


I wanted to share with you a function that I created to make the array_multisort process much easier for myself... There was some interesting things that I encountered and I will post that in the comments.



I created this function so that all I have to do is tell it what column I want to sort through in a one level deep multidimensional array.  You can Try this code in your browser to view the results



ex/

<?php



//Here is an array example

$test[0]['name'] = "David";

$test[0]['age'] = 28;

$test[1]['name'] = "Dennis";

$test[1]['age'] = 23;

$test[2]['name'] = "Joseph";

$test[2]['age'] = 42;



//Here is the Function



function sortmddata($array, $by, $order, $type){



//$array: the array you want to sort

//$by: the associative array name that is one level deep

////example: name

//$order: ASC or DESC

//$type: num or str

        

$sortby = "sort$by"; //This sets up what you are sorting by



$firstval = current($array); //Pulls over the first array



$vals = array_keys($firstval); //Grabs the associate Arrays



foreach ($vals as $init){

    $keyname = "sort$init";

    $$keyname = array();

}

//This was strange because I had problems adding

//Multiple arrays into a variable variable

//I got it to work by initializing the variable variables as arrays

//Before I went any further



foreach ($array as $key => $row) {

    

foreach ($vals as $names){

    $keyname = "sort$names";

    $test = array();

    $test[$key] = $row[$names];

    $$keyname = array_merge($$keyname,$test);

    

}



}



//This will create dynamic mini arrays so that I can perform

//the array multisort with no problem

//Notice the temp array... I had to do that because I 

//cannot assign additional array elements to a 

//varaiable variable            



if ($order == "DESC"){    

if ($type == "num"){

array_multisort($$sortby,SORT_DESC, SORT_NUMERIC,$array);

} else {

array_multisort($$sortby,SORT_DESC, SORT_STRING,$array);

}

} else {

if ($type == "num"){

array_multisort($$sortby,SORT_ASC, SORT_NUMERIC,$array);

} else {

array_multisort($$sortby,SORT_ASC, SORT_STRING,$array);

}

}



//This just goed through and asks the additional arguments

//What they are doing and are doing variations of

//the multisort



return $array;

}



//Now to test it



$test = sortmddata($test,'age','ASC','num');



print_r ($test);



//This will return

//Array ( 

//[0] => Array ([name] => Dennis [age] => 23 )

//[1] => Array ( [name] => David [age] => 28 )

//[2] => Array ( [name] => Joseph [age] => 42 )

//)



?>



There you go... please let me know what you think if you like.

php a-t-the-r-a-t-e chir.ag
05-Jan-2006 02:10


Re: phu at kungphu, 19-Dec-2005 11:36 



asort($test) will not let me specify which columns to sort ASC/DESC, NUMERIC/STRING etc.



I have data similar to what you specified. Now I want to sort $test by points DESC and name ASC. Here's my function that does it, based on suggestions on this page. It uses array_multisort (and hence acts just like it: preserving string-keys etc.)



<?php



  function arrayColumnSort()

  {

    $n = func_num_args();

    $ar = func_get_arg($n-1);

    if(!is_array($ar))

      return false;



    for($i = 0; $i < $n-1; $i++)

      $col[$i] = func_get_arg($i);



    foreach($ar as $key => $val)

      foreach($col as $kkey => $vval)

        if(is_string($vval))

          ${"subar$kkey"}[$key] = $val[$vval];



    $arv = array();

    foreach($col as $key => $val)

      $arv[] = (is_string($val) ? ${"subar$key"} : $val);

    $arv[] = $ar;



    call_user_func_array("array_multisort", $arv);

    return $ar;

  }



  $test["pete"]['points']=1;

  $test["pete"]['name']='Peter';



  $test["mike"]['points']=5;

  $test["mike"]['name']='Mike';



  $test["zoo"]['points']=2;

  $test["zoo"]['name']='John Zoo';



  $test["ab"]['points']=2;

  $test["ab"]['name']='John Ab';



  $test1 = $test;



  asort($test1);



  $test2 = arrayColumnSort("points", SORT_DESC, SORT_NUMERIC, "name", SORT_ASC, SORT_STRING, $test);



  print_r($test1); // asort

  print_r($test2); // arrayColumnSort



?>



Output from asort:



Array

(

    [pete] => Array

        (

            [points] => 1

            [name] => Peter

        )



    [ab] => Array

        (

            [points] => 2

            [name] => John Ab

        )



    [zoo] => Array

        (

            [points] => 2

            [name] => John Zoo

        )



    [mike] => Array

        (

            [points] => 5

            [name] => Mike

        )



)



Output from arrayColumnSort:



Array

(

    [mike] => Array

        (

            [points] => 5

            [name] => Mike

        )



    [ab] => Array

        (

            [points] => 2

            [name] => John Ab

        )



    [zoo] => Array

        (

            [points] => 2

            [name] => John Zoo

        )



    [pete] => Array

        (

            [points] => 1

            [name] => Peter

        )



)

phu at kungphu
19-Dec-2005 11:36


Notepad's example using asort/arsort will -not- work unless 'points' is defined -before- 'name'.



Running the posted code sorts by 'name', which was not the point of the previous posts.  Defining 'points' as 'apoints' also did not work; however, defining 'points' first yields correct sorting:



$test[0]['points']=1;

$test[0]['name']='Peter';



$test[1]['points']=5;

$test[1]['name']='Mike';



$test[2]['points']=2;

$test[2]['name']='John';



asort($test);



It appears asort uses the first defined element to sort a multidimensional array.

notepad at codewalkers dot com
09-Dec-2005 04:33


for you guys trying to sort scores on an associative multi-dimensional array, why are you creating your own functions?



<?php



$test[0]['name']='Peter';

$test[0]['points']=1;



$test[1]['name']='Mike';

$test[1]['points']=5;



$test[2]['name']='John';

$test[2]['points']=2;



asort($test);

// or even arsort();



?>



the above seems to work for me...

Shmee
30-Sep-2005 06:46


RWC�s code works very well until you get a �point� value greater then ten.  This is because the strcmp() function will return that 2 > 10 and 2 > 11 � 2 > 19 and so on. To compare number values over ten try a sort like this:



$test = multi_sort($test, $key = 'points');



function multi_sort($array, $akey)

{ 

  function compare($a, $b)

  {

     global $key;

     if ($a[$key]>$b[$key]){

         $varcmp = "1";

         return $varcmp;

     }

     elseif ($a[$key]<$b[$key]){

         $varcmp = "-1";

         return $varcmp;

     }

     elseif ($a[$key]==$b[$key]){

         $varcmp = "0";

         return $varcmp;

     }

  }

  usort($array, "compare");

  return $array;

}

RWC
25-Sep-2005 01:45


This is the simpler version of the function by AlberT.



A lot of times you have got an array like this:



$test[0]['name']='Peter';

$test[0]['points']=1;



$test[1]['name']='Mike';

$test[1]['points']=5;



$test[2]['name']='John';

$test[2]['points']=2;



You just want to sort on the index in the second dimension, ie. on points in the above example.

 

You can use the function below and call it like this:



$test = multi_sort($test, $key = 'points');



function multi_sort($array, $akey)

{  

  function compare($a, $b)

  {

     global $key;

     return strcmp($a[$key], $b[$key]);

  } 

  usort($array, "compare");

  return $array;

}



Note: to be able to use $key in the compare function, it can not simply be passed as a parameter. It has to be declared global and set somewhere outside of compare().

AlberT at SuperAlberT dot it
18-Jul-2005 06:59


a nice piece of code to do an "array_key_multi_sort()" is the following:



<?php

/**

 * orders a multidimentional array on the base of a label-key

 *

 * @param $arr, the array to be ordered

 * @param $l the "label" identifing the field

 * @param $f the ordering function to be used, 

 *    strnatcasecmp() by default

 * @return  TRUE on success, FALSE on failure.

 */

function array_key_multi_sort(&$arr, $l , $f='strnatcasecmp') {

        return usort($arr, create_function('$a, $b', "return $f(\$a['$l'], \$b['$l']);"));

}

?>

kencomer at kencomer dot com
12-Jun-2005 11:48

Michael Oelze at �M (myname) �T GMXdotDE
25-Apr-2005 09:15


I try array_multisort at first and it seems to work well. But then I program a page with cached datas (the arrays were saved in a session). Suddenly the sort function doesn't seem to work. There was no error in my script, so I try the reference on the variables. Then he manage to sort the arrays again.



So it seems that if you save your Arrays in a session your arrays are global variables and then 'array_multisort' doesn't sort the arrays despite it gives back 'true'.

 You must reference your variables and all work well:



session_start(); // restore variables (Arrays etc.)

.....

.....

array_multisort(&$Array1,&$Array2,&$Array3,...);

....

$_SESSION["Array1"]=$Array1;//

$_SESSION["Array2"]=$Array2;//Save Arrays in Session Data

$_SESSION["Array3"]=$Array3;//

......



Now you can store your Data Arrays in your Session and are able to sort them as you like...

stevec at NO-/ dot /-SPAM dot qiguang dot net
13-Apr-2005 08:19


Be careful when using array_multisort() on copies of arrays, as you might end up changing the original array.  Given the following code:



<?php

    $test1 = array(4,3,2,1);

    $test2 = $test1;

    $test3 = array('a', 'b', 'c', 'd');



    array_multisort($test2, SORT_ASC, $test3);



    echo 'test1:';

    print_r($test1);

    echo 'test2:';

    print_r($test2);

    echo 'test3:';

    print_r($test3);

?>



You would expect:



test1:Array

(

    [0] => 4

    [1] => 3

    [2] => 2

    [3] => 1

)

test2:Array

(

    [0] => 1

    [1] => 2

    [2] => 3

    [3] => 4

)

test3:Array

(

    [0] => d

    [1] => c

    [2] => b

    [3] => a

)



However, if you run the code, you actually get:



test1:Array

(

    [0] => 1

    [1] => 2

    [2] => 3

    [3] => 4

)

test2:Array

(

    [0] => 1

    [1] => 2

    [2] => 3

    [3] => 4

)

test3:Array

(

    [0] => d

    [1] => c

    [2] => b

    [3] => a

)



Note that the original ($test1) ends up being sorted even though it was never called by array_multisort().  To work around this, insert a statement to modify the copy ($test2) before calling array_multisort() on it.  The following code will produce the expected "correct" results:



<?php

    $test1 = array(4,3,2,1);

    $test2 = $test1;

    $test3 = array('a', 'b', 'c', 'd');



    $test2[0] = $test2[0];                // fix

    array_multisort($test2, SORT_ASC, $test3);

        

    echo 'test1:';

    print_r($test1);

    echo 'test2:';

    print_r($test2);

    echo 'test3:';

    print_r($test3);

?>



This seems to be a resurrection of the closed bug #8130.  Also, someone reported this behavior in bug #32031, but it was incorrectly labeled "bogus" in reference to bug #25359, which is a different issue.

joao at intrasystems dot com dot br
07-Apr-2005 12:27


Exemple of sorting multi-dimensional arrays by one of it's fields:



$result[0]['nome']='Joao';

$result[0]['order']=5;

$result[1]['nome']='Pedro';

$result[1]['order']=1;

$result[2]['nome']='Marcelo';

$result[2]['order']=3;



foreach($result as $res)

     $sortAux[] = $res['order'];



array_multisort($sortAux, SORT_ASC, $result);



print_r($result);



produces:



Array

(

    [0] => Array

        (

            [nome] => Pedro

            [order] => 1

        )



    [1] => Array

        (

            [nome] => Marcelo

            [order] => 3

        )



    [2] => Array

        (

            [nome] => Joao

            [order] => 5

        )



)

Toni
10-Nov-2004 03:30


An example to sort an array by 3 criteria:



$recordset is an array of results from a query to a database, that I sort using $matrix as auxiliary array. First numeric, Second and Third alphabetically.



<?php

for($idx=0;$idx<$toShow;$idx++){

    $matrix[0][$id]=$recordset[$id][0];

    $matrix[1][$id]=$recordset[$id][1];

    $matrix[2][$id]=$recordset[$id][10];    

}



array_multisort($matrix[0], SORT_DESC, SORT_NUMERIC,$matrix[1], SORT_STRING, SORT_ASC,$matrix[2], SORT_STRING, SORT_ASC);

?>

meddle at dzygn.com
05-Oct-2004 07:40


If you want to sort a multidomensional array by key name you cannot use array_multisort. ie: for an array named $archivos that prints like this:



Array

(

    [0] => Array

        (

            [index] => 0

            [name] => test

        )



    [1] => Array

        (

            [index] => 0

            [name] => watertaxi.jpg

        )



    [2] => Array

        (

            [index] => 0

            [name] => 2_0003.JPG

        )



    [3] => Array

        (

            [index] => 0

            [name] => 24A_0025.JPG

        )



    [4] => Array

        (

            [index] => 1

            [name] => _CIMG3501.JPG

        )



)



If I wanted to order by "name" I'd use:



function comparar($a, $b) {

        return strnatcasecmp($a["name"], $b["name"]);

}

usort($archivos, "comparar"); 



This function performs a case insensitive string comparison using a "natural order" algorithm (strnatcasecmp), resulting in:



Array

(

    [0] => Array

        (

            [index] => 0

            [name] => 2_0003.JPG

        )



    [1] => Array

        (

            [index] => 0

            [name] => 24A_0025.JPG

        )



    [2] => Array

        (

            [index] => 0

            [name] => test

        )



    [3] => Array

        (

            [index] => 0

            [name] => watertaxi.jpg

        )



    [4] => Array

        (

            [index] => 1

            [name] => _CIMG3501.JPG

        )



)

kat dot n0spam at audiogalaxy dot com
23-Aug-2001 10:25


If you're having problems with array_multisort changing variables in global space when it is called inside a function and you're not passing in the function parameters by reference you can alleviate the problem by calling array_multisort with its parameters by reference.





array_multisort(&$a, SORT_DESC, &$b);





More details here in my bug report:


bugs.php?id=12936