array_multisort

(PHP 4, PHP 5, PHP 7, PHP 8)

array_multisort — Sort multiple or multi-dimensional arrays

Description

array_multisort(
    array &$array1,
    mixed $array1_sort_order = SORT_ASC,
    mixed $array1_sort_flags = SORT_REGULAR,
    mixed ...$rest
): bool

array_multisort() can be used to sort several arrays at once, or a multi-dimensional array by one or more dimensions.

Associative (string) keys will be maintained, but numeric keys will be re-indexed.

Note:
If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.

Note:
Resets array's internal pointer to the first element.

Parameters

array1

An array being sorted.

array1_sort_order

The order used to sort the previous array argument. Either SORT_ASC to sort ascendingly or SORT_DESC to sort descendingly.

This argument can be swapped with array1_sort_flags or omitted entirely, in which case SORT_ASC is assumed.

array1_sort_flags

Sort options for the previous array argument:

Sorting type flags:

SORT_REGULAR - compare items normally (don't change types)
SORT_NUMERIC - compare items numerically
SORT_STRING - compare items as strings
SORT_LOCALE_STRING - compare items as strings, based on the current locale. It uses the locale, which can be changed using setlocale()
SORT_NATURAL - compare items as strings using "natural ordering" like natsort()
SORT_FLAG_CASE - can be combined (bitwise OR) with SORT_STRING or SORT_NATURAL to sort strings case-insensitively

This argument can be swapped with array1_sort_order or omitted entirely, in which case SORT_REGULAR is assumed.

rest

More arrays, optionally followed by sort order and flags. Only elements corresponding to equivalent elements in previous arrays are compared. In other words, the sort is lexicographical.

Return Values

Returns true on success or false on failure.

Examples

Example #1 Sorting multiple arrays

<?php
$ar1 = array(10, 100, 100, 0);
$ar2 = array(1, 3, 2, 4);
array_multisort($ar1, $ar2);

var_dump($ar1);
var_dump($ar2);
?>

In this example, after sorting, the first array will contain 0, 10, 100, 100. The second array will contain 4, 1, 2, 3. The entries in the second array corresponding to the identical entries in the first array (100 and 100) were sorted as well.

array(4) {
  [0]=> int(0)
  [1]=> int(10)
  [2]=> int(100)
  [3]=> int(100)
}
array(4) {
  [0]=> int(4)
  [1]=> int(1)
  [2]=> int(2)
  [3]=> int(3)
}

Example #2 Sorting multi-dimensional array

<?php
$ar = array(
       array("10", 11, 100, 100, "a"),
       array(   1,  2, "2",   3,   1)
      );
array_multisort($ar[0], SORT_ASC, SORT_STRING,
$ar[1], SORT_NUMERIC, SORT_DESC);
var_dump($ar);
?>

In this example, after sorting, the first array will transform to "10", 100, 100, 11, "a" (it was sorted as strings in ascending order). The second will contain 1, 3, "2", 2, 1 (sorted as numbers, in descending order).

array(2) {
  [0]=> array(5) {
    [0]=> string(2) "10"
    [1]=> int(100)
    [2]=> int(100)
    [3]=> int(11)
    [4]=> string(1) "a"
  }
  [1]=> array(5) {
    [0]=> int(1)
    [1]=> int(3)
    [2]=> string(1) "2"
    [3]=> int(2)
    [4]=> int(1)
  }
}

Example #3 Sorting database results

For this example, each element in the data array represents one row in a table. This type of dataset is typical of database records.

Example data:

volume | edition
-------+--------
    67 |       2
    86 |       1
    85 |       6
    98 |       2
    86 |       6
    67 |       7

The data as an array, called data. This would usually, for example, be obtained by looping with mysqli_fetch_assoc().

<?php
$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data[] = array('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data[] = array('volume' => 67, 'edition' => 7);
?>

In this example, we will order by volume descending, edition ascending.

We have an array of rows, but array_multisort() requires an array of columns, so we use the below code to obtain the columns, then perform the sorting.

<?php
// Obtain a list of columns
foreach ($data as $key => $row) {
$volume[$key]  = $row['volume'];
$edition[$key] = $row['edition'];
}

// you can use array_column() instead of the above code
$volume  = array_column($data, 'volume');
$edition = array_column($data, 'edition');

// Sort the data with volume descending, edition ascending
// Add $data as the last parameter, to sort by the common key
array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data);
?>

The dataset is now sorted, and will look like this:

volume | edition
-------+--------
    98 |       2
    86 |       1
    86 |       6
    85 |       6
    67 |       2
    67 |       7

Example #4 Case insensitive sorting

Both SORT_STRING and SORT_REGULAR are case sensitive, strings starting with a capital letter will come before strings starting with a lowercase letter.

To perform a case insensitive sort, force the sorting order to be determined by a lowercase copy of the original array.

<?php
$array = array('Alpha', 'atomic', 'Beta', 'bank');
$array_lowercase = array_map('strtolower', $array);

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

print_r($array);
?>

The above example will output:

Array
(
    [0] => Alpha
    [1] => atomic
    [2] => bank
    [3] => Beta
)

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User Contributed Notes 42 notes

down

221

jimpoz at jimpoz dot com ¶

13 years ago

I came up with an easy way to sort database-style results. This does what example 3 does, except it takes care of creating those intermediate arrays for you before passing control on to array_multisort(). 

<?php
function array_orderby()
{
$args = func_get_args();
$data = array_shift($args);
    foreach ($args as $n => $field) {
        if (is_string($field)) {
$tmp = array();
            foreach ($data as $key => $row)
$tmp[$key] = $row[$field];
$args[$n] = $tmp;
            }
    }
$args[] = &$data;
call_user_func_array('array_multisort', $args);
    return array_pop($args);
}
?>

The sorted array is now in the return value of the function instead of being passed by reference.

<?php
$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data[] = array('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data[] = array('volume' => 67, 'edition' => 7);

// Pass the array, followed by the column names and sort flags
$sorted = array_orderby($data, 'volume', SORT_DESC, 'edition', SORT_ASC);
?>

down

matt at bosc dot io ¶

8 years ago

One-liner function to sort multidimensionnal array by key, thank's to array_column

<?php

array_multisort (array_column($array, 'key'), SORT_DESC, $array);

?>

down

cagret at gmail dot com ¶

15 years ago

A more inuitive way of sorting multidimensional arrays using array_msort() in just one line, you don't have to divide the original array into per-column-arrays:

<?php

$arr1 = array(
    array('id'=>1,'name'=>'aA','cat'=>'cc'),
    array('id'=>2,'name'=>'aa','cat'=>'dd'),
    array('id'=>3,'name'=>'bb','cat'=>'cc'),
    array('id'=>4,'name'=>'bb','cat'=>'dd')
);

$arr2 = array_msort($arr1, array('name'=>SORT_DESC, 'cat'=>SORT_ASC));

debug($arr1, $arr2);

arr1:
0:
id: 1 (int)
name: aA (string:2)
cat: cc (string:2)
1:
id: 2 (int)
name: aa (string:2)
cat: dd (string:2)
2:
id: 3 (int)
name: bb (string:2)
cat: cc (string:2)
3:
id: 4 (int)
name: bb (string:2)
cat: dd (string:2)
arr2:
2:
id: 3 (int)
name: bb (string:2)
cat: cc (string:2)
3:
id: 4 (int)
name: bb (string:2)
cat: dd (string:2)
0:
id: 1 (int)
name: aA (string:2)
cat: cc (string:2)
1:
id: 2 (int)
name: aa (string:2)
cat: dd (string:2)

function array_msort($array, $cols)
{
$colarr = array();
    foreach ($cols as $col => $order) {
$colarr[$col] = array();
        foreach ($array as $k => $row) { $colarr[$col]['_'.$k] = strtolower($row[$col]); }
    }
$eval = 'array_multisort(';
    foreach ($cols as $col => $order) {
$eval .= '$colarr[\''.$col.'\'],'.$order.',';
    }
$eval = substr($eval,0,-1).');';
    eval($eval);
$ret = array();
    foreach ($colarr as $col => $arr) {
        foreach ($arr as $k => $v) {
$k = substr($k,1);
            if (!isset($ret[$k])) $ret[$k] = $array[$k];
$ret[$k][$col] = $array[$k][$col];
        }
    }
    return $ret;

}

?>

down

Robert C ¶

10 years ago

Hi,

I would like to see the next code snippet to be added to http://nl3.php.net/array_multisort

Purpose: Sort a 2-dimensional array on some key(s)

Advantage of function: 
- uses PHP's array_multisort function for sorting;
- it prepares the arrays (needed by array_multisort) for you;
- allows the sort criteria be passed as a separate array (It is possible to use sort order and flags.); 
- easy to set/overwrite the way strings are sorted (case insensitive instead of case sensitive, which is PHP's default way of sorting);
- performs excellent 

function MultiSort($data, $sortCriteria, $caseInSensitive = true)
{
  if( !is_array($data) || !is_array($sortCriteria))
    return false;       
  $args = array(); 
  $i = 0;
  foreach($sortCriteria as $sortColumn => $sortAttributes)  
  {
    $colList = array(); 
    foreach ($data as $key => $row)
    { 
      $convertToLower = $caseInSensitive && (in_array(SORT_STRING, $sortAttributes) || in_array(SORT_REGULAR, $sortAttributes)); 
      $rowData = $convertToLower ? strtolower($row[$sortColumn]) : $row[$sortColumn]; 
      $colLists[$sortColumn][$key] = $rowData;
    }
    $args[] = &$colLists[$sortColumn];

    foreach($sortAttributes as $sortAttribute)
    {      
      $tmp[$i] = $sortAttribute;
      $args[] = &$tmp[$i];
      $i++;      
     }
  }
  $args[] = &$data;
  call_user_func_array('array_multisort', $args);
  return end($args);
} 

Usage:

//Fill an array with random test data
define('MAX_ITEMS', 15);
define('MAX_VAL', 20);
for($i=0; $i < MAX_ITEMS; $i++)
  $data[] = array('field1' => rand(1, MAX_VAL), 'field2' => rand(1, MAX_VAL), 'field3' => rand(1, MAX_VAL) );

//Set the sort criteria (add as many fields as you want)
$sortCriteria = 
  array('field1' => array(SORT_DESC, SORT_NUMERIC), 
       'field3' => array(SORT_DESC, SORT_NUMERIC)
  );

//Call it like this:  
$sortedData = MultiSort($data, $sortCriteria, true);

down

nick ([AT]) nickyost ([DOT]) com ¶

12 years ago

USort function can be used to sort multidimensional arrays with almost no work whatsoever by using the individual values within the custom sort function.

This function passes the entire child element even if it is not a string. If it is an array, as would be the case in multidimensional arrays, it will pass the whole child array as one parameter.

Therefore, do something elegant like this:

<?php
// Sort the multidimensional array
usort($results, "custom_sort");
// Define the custom sort function
function custom_sort($a,$b) {
          return $a['some_sub_var']>$b['some_sub_var'];
     }
?>

This does in 4 lines what other functions took 40 to 50 lines to do. This does not require you to create temporary arrays or anything. This is, for me, a highly preferred solution over this function.

Hope it helps!

down

frank at overdrunk dot net ¶

15 years ago

down

lingtalfi ¶

3 years ago

For database like sorting, here is my 2 cents:

<?php
/**
 * The RowsSortHelperTool class.
 */
class RowsSortHelperTool
{

/**
     * Sorts the given array, based on the given sorts.
     *
     * The sorts argument is an array of field => direction,
     *
     * with:
     *
     * - field: string, the name of the property to sort the rows with
     * - direction: string (asc|desc), the direction of the sort
     *
     *
     * @param array $rows
     * @param array $sorts
     * @return array
     */
public static function sort(array &$rows, array $sorts)
    {

$args = [];

        foreach ($sorts as $field => $direction) {
$col = array_column($rows, $field);
$args[] = $col;

            if ('asc' === $direction) {
$args[] = SORT_ASC;
            } else {
$args[] = SORT_DESC;
            }
        }
$args[] = &$rows;
call_user_func_array("array_multisort", $args);
    }
}

?>

Use it like this:

<?php
$data[] = array('volume' => 67, 'edition' => 2, 'mine' => 5);
$data[] = array('volume' => 86, 'edition' => 1, 'mine' => 5);
$data[] = array('volume' => 85, 'edition' => 6, 'mine' => 5);
$data[] = array('volume' => 98, 'edition' => 2, 'mine' => 5);
$data[] = array('volume' => 86, 'edition' => 6, 'mine' => 4);
$data[] = array('volume' => 86, 'edition' => 6, 'mine' => 5);
$data[] = array('volume' => 67, 'edition' => 7, 'mine' => 5);

RowsSortHelperTool::sort($data, [
'volume' => 'desc',
'edition' => 'asc',
'mine' => 'desc',
]);

az($data);

?>

Will display something like this:

array(7) {
  [0] => array(3) {
    ["volume"] => int(98)
    ["edition"] => int(2)
    ["mine"] => int(5)
  }
  [1] => array(3) {
    ["volume"] => int(86)
    ["edition"] => int(1)
    ["mine"] => int(5)
  }
  [2] => array(3) {
    ["volume"] => int(86)
    ["edition"] => int(6)
    ["mine"] => int(5)
  }
  [3] => array(3) {
    ["volume"] => int(86)
    ["edition"] => int(6)
    ["mine"] => int(4)
  }
  [4] => array(3) {
    ["volume"] => int(85)
    ["edition"] => int(6)
    ["mine"] => int(5)
  }
  [5] => array(3) {
    ["volume"] => int(67)
    ["edition"] => int(2)
    ["mine"] => int(5)
  }
  [6] => array(3) {
    ["volume"] => int(67)
    ["edition"] => int(7)
    ["mine"] => int(5)
  }
}

down

zequez at gmail dot com ¶

14 years ago

Easiest way I find out to sort an entire multidimensional array by one element of it:


<?php

$multiArray = Array(

    Array("id" => 1, "name" => "Defg"),

    Array("id" => 2, "name" => "Abcd"),

    Array("id" => 3, "name" => "Bcde"),

    Array("id" => 4, "name" => "Cdef"));

$tmp = Array();

foreach($multiArray as &$ma)

$tmp[] = &$ma["name"];

array_multisort($tmp, $multiArray);

foreach($multiArray as &$ma)

    echo $ma["name"]."<br/>";


/* Outputs

    Abcd

    Bcde

    Cdef

    Defg

*/

?>



^-^

down

RWC ¶

18 years ago

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().

down

faugeron dot loic at gmail dot com ¶

8 years ago

Improving Example #3 (Sorting database results): using <?php array_column ?> (PHP >= 5.5) and <?php call_user_func_array ?> it becomes possible to build your sortings (sorting by one or many fields):

<?php

$data = [
    [
'id' => '168ac7f8-c918-4e99-90ee-5d7590fe61ce',
'name' => 'Arthur Dent',
    ],
    [
'id' => 'e3ad45ee-7cae-4cca-bd7b-2eb6b57b6457',
'name' => 'Ford Prefect',
    ],
    [
'id' => 'a426aef2-19e2-412a-8339-5458cf6ae416',
'name' => 'Trillian Astra',
    ],
];
$sortings = [
    [
'field' => 'id',
'direction' => SORT_DESC,
    ],
];

$args = [];
$key = 0;
foreach ($sortings as $sorting) {
$args[$key] = array_column($data, $sorting['field']);
$args[$key + 1] = $sorting['direction'];
$key += 2;
}
$args[] = $data;
call_user_func_array('array_multisort', $args);

// $data is now sorted by ID in descending order.
?>

down

nospam at nospam dot com ¶

8 years ago

Super easy and simple way to sort a keyed multiarray while maintaining all associative keys, including numeric!

Preserves the original multiarray order if the sorting values are equal.

<?php
// sorts multiarray by a subarray value while preserving all keys, also preserves original order when the sorting values match
function maSort($ma = '', $sortkey = '', $sortorder = 1) { // sortorder: 1=asc, 2=desc
if ($ma && is_array($ma) && $sortkey) { // confirm inputs
foreach ($ma as $k=>$a) $temp["$a[$sortkey]"][$k] = $a; // temp ma with sort value, quotes convert key to string in case numeric float
if ($sortorder == 2) { // descending
krsort($temp);
    } else { // ascending
ksort($temp);
    }
$newma = array(); // blank output multiarray to add to
foreach ($temp as $sma) $newma += $sma; // add sorted arrays to output array
unset($ma, $sma, $temp); // release memory
return $newma;
  }
}
?>

down

brettz9 throu gh yah ¶

17 years ago

Often, one may have a group of arrays which have parallel data that need to be kept associated with each other (e.g., the various attribute values of a group of elements might be stored in their own arrays). Using array_multisort as is, by specifying additional fields, it is possible, as in the documentation example cited below, that this association will be lost. 

To take this example set of data from the documentation:
<?php
$ar1 = array("10", 100, 100, "a");
$ar2 = array(1, 3, "2", 1);
?>

The example goes on to sort it this way:
<?php
array_multisort($ar1, $ar2);
?>

In this case, although the "10" remains associated with the first '1' after being sorted, the "2" and '3' are reversed from their original order.

In order to sort by one field only (yet still have the other array(s) being correspondingly sorted), one can use array_keys (which makes an array out of the keys) to ensure that no further sub-sorting is performed. This works because array_keys is making an array for which no duplicates can exist (since keys will be unique), and thus, the subsequent fields will have no relevance as far as subsorting.

So, using the above data, we can perform this sort instead:
<?php
$ar3 = array_keys($ar1);
array_multisort($ar1, $ar3, $ar2);
?>

which, when $ar1 and $ar2 are dumped gives:

array(4) {
  [0]=> string(2) "10"
  [1]=> string(1) "a"
  [2]=> int(100)
  [3]=> int(100)
}
array(4) {
  [0]=>  int(1)
  [1]=>  int(1)
  [2]=>  int(3)
  [3]=>  string(1) "2"
}

down

m dot michalczyk at gmail dot com ¶

15 years ago

Here is useful example based on za at byza dot it solution to sort multidimensional objects by any dimension.
za at byza dot it
<?php
/* Example structure */
class person{
    function __construct($firstName, $lastName, $title, $position){
$this->firstName = $firstName;
$this->lastName = $lastName;
$this->title = new title($title);
$this->position = new position($position);
    }
}
class title{
    function __construct($name){
$this->name = $name;
    }

}
class position{
    function __construct($name){
$this->name = $name;
    }

}

$array[] = new person('Piotr', 'Sobiepanek', 'b', 'b');
$array[] = new person('Piotr', 'Kowalski', 'b', 'a');
$array[] = new person('Piotr', 'Michalski', 'a', 'a');
$array[] = new person('Jozef', 'Smietana', 'a', 'b');
$array[] = new person('Jozef', 'Cmietana', 'a', 'b');
$array[] = new person('Marcin', 'Kondraciuk', 'c', 'b');
$array[] = new person('Maksym', 'Kondraciuk', 'c', 'd');
$array[] = new person('Ambrozy', 'Kondraciuk', 'c', 'd');
$array[] = new person('Alojzy', 'Kondraciuk', 'c', 'd');

array_sort($array, 'title->name', 'position->name', 'lastName');
print_r($array);

/* Source */

function hod(&$base, $path){
$keys = explode("->", $path);
$keys[0] = str_replace('$', '', $keys[0]);
$expression = '$ret = ';
$expression.= '$';
    foreach ($keys as $key){
        if (++$licz == 1){
$expression.= 'base->';            
        } else {
$expression.= $key.'->';
        }
    }
$expression = substr($expression, 0, -2);
$expression.= ';';
    eval($expression);
    return $ret;
}

function array_sort_func($a,$b=NULL) {
   static $keys;
   if($b===NULL) return $keys=$a;
   foreach($keys as $k) {
      if($k[0]=='!') {
$k=substr($k,1);
         if(hod($a, '$a->'.$k)!==hod($b, '$b->'.$k)) {
            return strcmp(hod($b, '$b->'.$k),hod($a, '$a->'.$k));
         }
      }
      else if(hod($a, '$a->'.$k)!==hod($b, '$b->'.$k)) {
         return strcmp(hod($a, '$a->'.$k),hod($b, '$b->'.$k));
      }
   }
   return 0;
}

function array_sort(&$array) {
   if(!$array) return $keys;
$keys=func_get_args();
array_shift($keys);
array_sort_func($keys);
usort($array,"array_sort_func");       
}
?>

down

Magento-User ¶

10 years ago

When sorting an array of (complex) objects, this function can give you a "Fatal error:  Nesting level too deep" since it directly compares elements in later arrays if the elements in earlier ones compare equal. This can be worked around with the Flag-Parameter:
<?php 
$sortKeys = array_map($extractKey, $lotsOfComplexObjects);
array_multisort($sortKeys, $lotsOfComplexObjects, SORT_ASC, SORT_NUMERIC);
?>
I'm replacing an 'uasort()'-call which is significantly slower since it leads to a lot of calls to the comparison-function but most of the objects involved are recursive.

If this 'trick' gives a wrong order,  you need a better key.

down

Patrick Adrichem ¶

10 years ago

If you do not have PHP 5.4 installed yet and you cannot use SORT_NATURAL. This function sorts arrays natural multi-dimensional based on key value

this function can be used for arrays as

array ( name => array( key => value ) )
and

array( name => value ).

arrays as array( name => array( key => value), name => value) are not supported.

<?php
static function natcasesortRecursive(&$aArray)
        {
$bHasArrays = false;
            foreach ($aArray as $sKey => &$mValue)
            {
                if (true === is_array($mValue))
                {
self::natcasesortRecursive($mValue);
$bHasArrays = true;
                }
            }
            if (true === $bHasArrays)
            {
uksort($aArray, 'strnatcasecmp');
            }
            else
            {
natcasesort($aArray);
            }
        }
?>

down

jcharpentier at darkmira dot fr ¶

10 years ago

There is a lack of precision for the second example :

Example #2 Sorting multi-dimensional array

The explanation is :
"In this example, [...] The second will contain 1, 3, "2", 2, 1 (sorted as numbers, in descending order). "
This could be misunderstood cause a sort as numbers in descending order will be 1, 1, "2", 2, 3.  

My proposal is as follows (in a best english should be great ^^) :
"In this example, [...] The second will contain 1, 3, "2", 2, 1 (sorted as well as first one, except for values 3 and "2" sorted as numbers, in descending order).  Because they are corresponding to the identical entries in the first array (100 and 100) which couldn't be sorted at first time."

down

alexander dot v at zend dot com ¶

14 years ago

array_multisort works normally in php 5.3, but it forces arguments to be references.

It doesn't make differences for common array_multisort() usage, but makes "problems" for sorting variable number of arrays where call_user_func_array() function is involved. 

So all sorting arrays have to be collected into new one as a references to array variables:

<?php
$sortArgs = array();

for (...) {
    ...
$sortArgs[] = &$valuesArray;
    ...
}

call_user_func_array('array_multisort', $sortArgs);
?>

This (requiring arguments to be a reference) is not actually a problem since source array will not be sorted otherwise.

Important note!
Don't forget to destroy $valuesArray variable if you use it over each array_multisort() argument processing iteration.
If you don't do it, all array_multisort() arguments will contain the same array:

<?php
for (...) {
    ...
$sortArgs[] = &$valuesArray;
    unset($valuesArray);
    ...
}
?>

And the last important thing :)
Collect sorting arrays somewhere. PHP 5.3 will transfer reference into value (when $valuesArray is destroyed) and you will get "Parameter 1 to array_multisort() expected to be a reference, value given" warning again otherwise.

Final code should look like this:

<?php
$sortArgs = array();
$sortFieldValues = array();

for (...) {
    ...
$sortFieldValues[] = &$valuesArray;
$sortArgs[] = &$valuesArray;
    unset($valuesArray);
    ...
}

call_user_func_array('array_multisort', $sortArgs);
?>

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mech.cx ¶

15 years ago

I was (as near everyone here :-) looking to sort 2-dimensional arrays by certain fields in the associative sub-arrays.
What I didn't like about the documentation examples is that you need to loop through the input array to create sub arrays first, then use those in the function call.

"php a-t-the-r-a-t-e chir.ag" (http://www.php.net/manual/en/function.array-multisort.php#60401) wrote a quite cunning wrapper function, I rewrote it slightly, changing variable names and adding comments (for my sanity :-) mostly.
One snag I found: the input array is passed to array_multisort as last argument, but the changed array is not the one that is returned. Passing it by reference fixed that. This seems to be caused by the whole thing sitting inside the call_user_func_array, as shown below.

<?php

$points = array(1, 5, 2, 2);
$names  = array('peter', 'mike', 'john Zoo', 'john Ab');

$source = array (
  array ( 'points' => 1, 'name' => 'Peter'),
  array ( 'points' => 5, 'name' => 'Mike'),
  array ( 'points' => 2, 'name' => 'John Zoo'),
  array ( 'points' => 2, 'name' => 'John Ab')
);

call_user_func_array('array_multisort', array($points, SORT_DESC, SORT_NUMERIC, $names, SORT_ASC, SORT_STRING, $source)); // doesn't work
print_r($source);
call_user_func_array('array_multisort', array($points, SORT_DESC, SORT_NUMERIC, $names, SORT_ASC, SORT_STRING, &$source)); // works!
print_r($source);

// Call like arrayColumnSort('points', SORT_DESC, SORT_NUMERIC, 'name', SORT_ASC, SORT_STRING, $source);

// Slightly adapted from http://www.php.net/manual/en/function.array-multisort.php#60401

// arrayColumnSort(string $field, [options, ], string $field2, [options, ], .... , $array) /

//____________________
// arrayColumnSort() /
function arrayColumnSort() {
$args  = func_get_args();
$array = array_pop($args);
  if (! is_array($array)) return false;
// Here we'll sift out the values from the columns we want to sort on, and put them in numbered 'subar' ("sub-array") arrays.
  //   (So when sorting by two fields with two modifiers (sort options) each, this will create $subar0 and $subar3)
foreach($array as $key => $row) // loop through source array
foreach($args as $akey => $val) // loop through args (fields and modifiers)
if(is_string($val))             // if the arg's a field, add its value from the source array to a sub-array
${"subar$akey"}[$key] = $row[$val];
// $multisort_args contains the arguments that would (/will) go into array_multisort(): sub-arrays, modifiers and the source array
$multisort_args = array(); 
  foreach($args as $key => $val)
$multisort_args[] = (is_string($val) ? ${"subar$key"} : $val);
$multisort_args[] = &$array;   // finally add the source array, by reference
call_user_func_array("array_multisort", $multisort_args);
  return $array;
}

?>

down

Anonymous ¶

27 days ago

Arrays in PHP are "ordered maps".  The "order" is internal, and has nothing to do with the numerical values of the keys.
Array_multisort() seems to sort based on this internal order.  It DOES NOT maintain numeric key association, and then renumber based on this association.  It maintains internal order association, and numeric keys are renumbered based on this association.  String-keys do not maintain key association or internal order association, at least when mixed with numeric keys.
In other words, your 2 arrays must be built similarly or perhaps unexpected results will be obtained.

<?php
$foo=array("foo"=>"fazz", 7, 5,"sing"=>"soft", 9, 2, 0,"fing"=>"fong", 8, 1, 4);
$bar=array("bar"=>"bazz",17,45,"sing"=>"loud",29,72,90,"bing"=>"bong",38,81,54);
array_multisort($foo, $bar);
echo var_dump($foo),"<br><br>",var_dump($bar),"<br><br>";
?>
array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(4) [4]=> int(5) [5]=> int(7) [6]=> int(8) [7]=> int(9) ["foo"]=> string(4) "fazz" ["fing"]=> string(4) "fong" ["sing"]=> string(4) "soft" }

array(11) { [0]=> int(90) [1]=> int(81) [2]=> int(72) [3]=> int(54) [4]=> int(45) [5]=> int(17) [6]=> int(38) [7]=> int(29) ["bar"]=> string(4) "bazz" ["bing"]=> string(4) "bong" ["sing"]=> string(4) "loud" }

<?php
$foo=array("foo"=>"fazz", 7, 5,"sing"=>"soft", 9, 2, 0,"fing"=>"fong", 8, 1, 4);
$bar=array(17,45,29,72,90,"sing"=>"loud",38,81,54,"bing"=>"bong","bar"=>"bazz");
array_multisort($foo, $bar);
echo var_dump($foo),"<br><br>",var_dump($bar),"<br><br>";
?>
array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(4) [4]=> int(5) [5]=> int(7) [6]=> int(8) [7]=> int(9) ["foo"]=> string(4) "fazz" ["fing"]=> string(4) "fong" ["sing"]=> string(4) "soft" }

array(11) { [0]=> int(38) ["bar"]=> string(4) "bazz" ["sing"]=> string(4) "loud" ["bing"]=> string(4) "bong" [1]=> int(29) [2]=> int(45) [3]=> int(54) [4]=> int(90) [5]=> int(17) [6]=> int(81) [7]=> int(72) }

My Arrays in my project were built using the <?php $foo[]=$filename ?> syntax in a loop, with a string-keyed property added in at a random position within the loop to store directory names if they were found, while a matching array was built with the complete file-paths, but no directory info.  Can't use Array_multisort to sort both arrays by the filenames, even after adding a "fake" matching string-keyed property to the array of filepaths after-the-fact.
I had to build my array of filepaths in a separate variable, sort, then add it to the filenames array as a string-keyed property after the fact.

down

Sbastien ¶

1 year ago

The shuttle operator can be a smart alternative to array_multisort() for multidimensional and/or custom sorting.

<?php

$data = [
    ['name' => 'John Smith', 'status' => 'Offline'],
    ['name' => 'Anne Onyme', 'status' => 'Online'],
    ['name' => 'Alan Smithee', 'status' => 'Online'],
];

// Online first, then alphabetic name order
usort($data, fn ($a, $b) => [
    ['Online' => 1, 'Offline' => 2][$a['status']],
$a['name'],
] <=> [
    ['Online' => 1, 'Offline' => 2][$b['status']],
$b['name'],
]);

print_r($data);

/*
Array
    [0] => Array
        [name] => Alan Smithee
        [status] => Online
    [1] => Array 
        [name] => Anne Onyme
        [status] => Online
    [2] => Array 
        [name] => John Smith
        [status] => Offline
*/

down

498936940 at qq dot com ¶

2 years ago

Arbitrarily sort the two-dimensional array according to multiple keys:

```
array_multisort (
    array_column($array, 'key1'), SORT_ASC,
    array_column($array, 'key2'), SORT_DESC,
    array_column($array, 'key3'), SORT_ASC,
    array_column($array, 'key4'), SORT_DESC,
    $array
);
```

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Hayley Watson ¶

6 years ago

Thin wrapper around array_multisort() so that, when sorting an array of associative arrays, you can specify the columns to sort on by their name, instead of having to pull them out as explicit arrays. Note that you can sort on numerically-indexed columns too, provided you cast the index to a string first (otherwise they'll get confused with the SORT_* constants).

<?php
function array_multisort_by_column(&$array, ...$spec)
{
    return array_multisort($array, ...array_map(function($s)use($array)
    {
        return is_string($s) ? array_column($array, $s) : $s;
    }, $spec));
}
?>

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scott - evolove - net - work it out ¶

18 years ago

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;    
}
--------------------

down

ArkieGuy ¶

6 years ago

<?php  

/**
 *  array_multisort wrapper function -- Sorts Data array on array of Keys
 *  
 *  $data : This is the multidiminsional array to sort
 *  $keys : An array of arrays holding "Key" field names and optional Order / flags
 *  
 *  Example:  $keys[2] = [ 'Animal', SORT_DESC, SORT_REGULAR | SORT_FLAG_CASE ];
 *            $keys[1] = [ 'Name' ];
 *
 *  Syntax:   if( multiSort( $data, $keys ) ) print_r( $data );
 *
 *  Returns TRUE on success or FALSE on failure.
 */
function multiSort( &$data, $keys ) {

// Sort the Keys - this allows for passing in the key array out of order
ksort( $keys );

//  Walk Keys array building arguments to pass to call_user_function 
  //  (must be indexed 0-n with n being the data to sort)
foreach( $keys as $key ) {
//  Walk through the list of key parameters
foreach( $key as $element => $value )
        if( $element == 0 )
//  Add an array containing the column values for the named $data column
$args[] = array_column( $data, $value );
        else
//  Add the inetger value passed in for the order / flags
            //  NOTE: if you try to send a string value (like from an INI) to
            //        array_multisort for sort_order or sort_flags, you get 
            //        "Argument #x is expected to be an array or a sort flag".
            //        Casting to int solves this issue
$args[] = (int)$value;
  }

//  Add the array to be sorted to the arg list  
$args[] = &$data;

//  Call array_multisort to sort the array in keys order
return( call_user_func_array( 'array_multisort', $args ) );
}

/* Example */

echo "<PRE>";

//  Data array (can be associative array or you can use column number)
$data = [
  ['Name' => 'Brown', 'Animal' => 'Dog'],
  ['Name' => 'Smith', 'Animal' => 'Cat'],
  ['Name' => 'Jones', 'Animal' => 'Dog'],
  ['Name' => 'Jones', 'Animal' => 'Pig'],
  ['Name' => 'Bennett', 'Animal' => 'Cat'],
  ['Name' => 'Astor', 'Animal' => 'Cat'],
  ['Name' => 'Jones', 'Animal' => 'Cat'],
];

//  Array containing "keys" - each key is the name of the column and
//    optionally a sort order and / or  sort flags
//  Will sort by Name and then Animal because the keys array is key sorted 
//    before it's used.
$keys[2] = [ 'Animal', SORT_DESC, SORT_REGULAR | SORT_FLAG_CASE ];
$keys[1] = [ 'Name' ];  

//call the wrapper function
if( ! multiSort( $data, $keys ) )
    die( 'Sort Failed' );

print_r( $data );
?>

down

walterquez at gmail dot com ¶

6 years ago

To sort a simple multi dimensional array, use the array itself as the modifier. This will sort based on the first column. No need to write a custom function.

$data = array(
    array('volume' => 67, 'edition' => 2),
    array('volume' => 86, 'edition' => 1),
    array('volume' => 85, 'edition' => 6),
    array('volume' => 98, 'edition' => 2),
    array('volume' => 86, 'edition' => 6),
    array('volume' => 67, 'edition' => 7)
)

array_multisort($data, $data);

down

-2

qasastechnology at gmail dot com ¶

5 years ago

Case insensitive sorting
To perform a case insensitive sort

$array = [
     [
       'name' => 'b',
       'label' => 'ball'
    ],
     [
       'name' => 'a',
       'label' => 'apple'
    ],
     [
       'name' => 'l',
       'label' => 'Lighting'
    ],
     [
       'name' => 'w',
       'label' => 'With'
    ]

];

public function sortArray($array) {

        if (count($array)) {
            array_multisort(array_map(function($element) {
                return strtolower($element['label']);
            }, $array), SORT_ASC, $array);
        }

        return $array;
    }

down

matt at wennersten dot org ¶

9 years ago

Many users have contributed nifty wrapper functions for generalizing array_multisort. However, some of us may just want a simple example that illustrates how to sort an arbitrary multi-dimensional array, such as a database result set, on a named field. 

Consider an array of voice recordings (Clip objects) that are stored on a file system, and referenced via a database table:

    $fetchClipQuery = "SELECT * from voiceclips";
    if ( !$result = $this->db->query($fetchClipQuery) ) {
            $errormessage = $this->db->errno;
            $errormessage .= $this->db->error;
        } else {
            while($row = $result->fetch_assoc()){
                $clip = new Clip(); 
                $clip->populate($row['clipURL']);
                $clips[] = array("speaker"=>$row['speaker'],"duration"=>$row['duration'],"clip"=>$clip);
            }

//we now have an array called clips[] that looks like this:

array("speaker"=>"Obama","duration"=>"22:00","clip"=>...<some arbitrary object>...);

        //suppose we want to sort the array by speaker
        $sortkeyname = "speaker";
        //do the sort
        $sortkeyarray = array();
        foreach ($clips as $key => $row){
            $sortkeyarray[$key] = $row[$sortkeyname];
        }
        array_multisort($sortkeyarray, SORT_DESC, $clips);

           //suppose we want to sort the array by duration
        $sortkeyname = "duration";
        //do the sort
        $sortkeyarray = array();
        foreach ($clips as $key => $row){
            $sortkeyarray[$key] = $row[$sortkeyname];
        }
        array_multisort($sortkeyarray, SORT_DESC, $clips);

...etc.

down

plugboard at web dot de ¶

11 years ago

multisort an Array of Objects: 

example object [$object with array of objects]: (class: test) 
---------------------------------- 

test Object (
  [Artikel] => Array (
      [0] => test Object (
            [id] => 1
            [title] => CCCC
         )
      [1] => test Object (
            [id] => 2
            [title] => AAAA
         )
      [2] => test Object (
            [id] => 3
            [title] => DDDD
         )
      [3] => test Object (
            [id] => 4
            [title] => BBBB
         )
   )
)

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

Simple PHP function: sort_arr_of_obj()

<?php 
// -------------------------------------- 

/* 
* -------- function arguments -------- 
*   $array ........ array of objects
*   $sortby ....... the object-key to sort by
*   $direction ... 'asc' = ascending
* --------
*/

function sort_arr_of_obj($array, $sortby, $direction='asc') {

$sortedArr = array();
$tmp_Array = array();

    foreach($array as $k => $v) {
$tmp_Array[] = strtolower($v->$sortby);
    }

    if($direction=='asc'){
asort($tmp_Array);
    }else{
arsort($tmp_Array);
    }

    foreach($tmp_Array as $k=>$tmp){
$sortedArr[] = $array[$k];
    }

    return $sortedArr;

}


// -------------------------------------- 
?>

example call: 
---------------------------------- 

<?php 

$sorted->Artikel = sort_arr_of_obj($object->Artikel,'title','asc');

?>

example result: $sorted (class: test) 
---------------------------------- 

test Object (
  [Artikel] => Array (
      [0] => test Object (
            [id] => 2
            [title] => AAAA
         )
      [1] => test Object (
            [id] => 4
            [title] => BBBB
         )
      [2] => test Object (
            [id] => 1
            [title] => CCCC
         )
      [3] => test Object (
            [id] => 3
            [title] => DDDD
         )

   )
)

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

:)

down

info at ichier dot de ¶

13 years ago

if you want to sort an array by columns, this is the function to do it.


<?php

function array_csort() {        //coded by Ichier2003

$args = func_get_args();

$marray = array_shift($args); 

$msortline = 'return(array_multisort(';

    foreach ($args as $arg) {

$i++;

        if (is_string($arg)) {

            foreach ($marray as $row) {

$sortarr[$i][] = $row[$arg];

            }

        } else {

$sortarr[$i] = $arg;

        }

$msortline .= '$sortarr['.$i.'],';

    }

$msortline .= '$marray));';

    eval($msortline);

    return $marray;

}

?>

down

thierryzo at hotmail dot fr ¶

13 years ago

//A very simple way to sort arrays with this kind of structure.

<?php
    $myArray =array( 
        array("NUMCIE" => "001","REF" => "RXL","COLOR" => "RED","L1" => 4),
        array("NUMCIE" => "001","REF" => "RXL","COLOR" => "BLUE","L1" => 6),
        array("NUMCIE" => "001","REF" => "RHQ","COLOR" => "RED","L1" => 4),
        array("NUMCIE" => "002","REF" => "RXL","COLOR" => "YELLOW","L1" => 8));


    foreach($myArray as $c=>$key) {
$sort_numcie[] = $key['NUMCIE'];
$sort_ref[] = $key['REF'];
$sort_color[] = $key['COLOR'];
    }

array_multisort($sort_numcie, SORT_ASC, $sort_ref, SORT_STRING, $myArray);
print_r($myArray);

?>     

//Result array

Array
(
    [0] => Array
        (
            [NUMCIE] => 001
            [REF] => RHQ
            [COLOR] => RED
            [L1] => 4
        )

    [1] => Array
        (
            [NUMCIE] => 001
            [REF] => RXL
            [COLOR] => BLUE
            [L1] => 6
        )

    [2] => Array
        (
            [NUMCIE] => 001
            [REF] => RXL
            [COLOR] => RED
            [L1] => 4
        )

    [3] => Array
        (
            [NUMCIE] => 002
            [REF] => RXL
            [COLOR] => YELLOW
            [L1] => 8
        )

)

down

Jaak Tamre ¶

13 years ago

I had a problem with sorting SimpleXMLElement list. I found a nice short solution.


I have an array of ticket objects: $ticketList = $xml->Tickets;


<?php

// Sort by ValidOnDate

$tickets = array();

$valid = array();

foreach ($ticketList as $row) {

$tickets[] = $row;

$valid[] = DateHandler::parseDate($row->ValidOnDate);

}

array_multisort($valid, SORT_DESC, $tickets);

?>



Just make an array of object items you want to sort by and a new array for the same objects which will be reordered like the first array.


Ps: my own parseDate(date) returns unix timestamp for different date formats.

down

Zbigniew Heintze http://bigweb.pl ¶

15 years ago

<?php

/**

 * Sort DB result

 *

 * @param array $data Result of sql query as associative array

 * 

 * Rest of parameters are optional 

 * [, string $name  [, mixed $name or $order  [, mixed $name or $mode]]]

 * $name string - column name i database table

 * $order integer - sorting direction ascending (SORT_ASC) or descending (SORT_DESC)

 * $mode integer - sorting mode (SORT_REGULAR, SORT_STRING, SORT_NUMERIC)

 * 

 * <code>

 * <?php

 * // You can sort data by several columns e.g.

 * $data = array();

 * for ($i = 1; $i <= 10; $i++) {

 *     $data[] = array( 'id' => $i, 

 *                      'first_name' => sprintf('first_name_%s', rand(1, 9)), 

 *                      'last_name' => sprintf('last_name_%s', rand(1, 9)), 

 *                      'date' => date('Y-m-d', rand(0, time()))

 *                  );

 * }

 * $data = sortDbResult($data, 'date', SORT_DESC, SORT_NUMERIC, 'id');

 * printf('<pre>%s</pre>', print_r($data, true)); 

 * $data = sortDbResult($data, 'last_name', SORT_ASC, SORT_STRING, 'first_name', SORT_ASC, SORT_STRING);     

 * printf('<pre>%s</pre>', print_r($data, true)); 

 * ?>

 * </code>

 * 

 * @return array $data - Sorted data

 */

function sortDbResult(array $data /*$name, $order, $mode*/) {

$_argList = func_get_args();

$_data = array_shift($_argList);

    if (empty($_data)) {

        return $_data;

    }

$_max = count($_argList);

$_params = array();

$_cols = array();

$_rules = array();

    for ($_i = 0; $_i < $_max; $_i += 3) 

    {

$_name = (string) $_argList[$_i];

        if (!in_array($_name, array_keys(current($_data)))) {

            continue;

        }

        if (!isset($_argList[($_i + 1)]) || is_string($_argList[($_i + 1)])) {

$_order = SORT_ASC;

$_mode = SORT_REGULAR;

$_i -= 2;

        } else if (3 > $_argList[($_i + 1)]) {

$_order = SORT_ASC;

$_mode = $_argList[($_i + 1)];

$_i--;

        } else {

$_order = $_argList[($_i + 1)] == SORT_ASC ? SORT_ASC : SORT_DESC;

            if (!isset($_argList[($_i + 2)]) || is_string($_argList[($_i + 2)])) {

$_mode = SORT_REGULAR;

$_i--;

            } else {

$_mode = $_argList[($_i + 2)];

            }

        }

$_mode = $_mode != SORT_NUMERIC 

? $_argList[($_i + 2)] != SORT_STRING ? SORT_REGULAR : SORT_STRING

: SORT_NUMERIC;

$_rules[] = array('name' => $_name, 'order' => $_order, 'mode' => $_mode);

    }

    foreach ($_data as $_k => $_row) {

        foreach ($_rules as $_rule) {

            if (!isset($_cols[$_rule['name']])) {

$_cols[$_rule['name']] = array();

$_params[] = &$_cols[$_rule['name']];

$_params[] = $_rule['order'];

$_params[] = $_rule['mode'];

            }

$_cols[$_rule['name']][$_k] = $_row[$_rule['name']];

        }

    }

$_params[] = &$_data;

call_user_func_array('array_multisort', $_params);

    return $_data;

}

?>

down

matt at idizinc dot com ¶

15 years ago

I looked on some forms for an answer to this simple problem and couldn't find one so I came up with a solution that may help in some situations.

How do you sort an array by a field in that array and resolve numeric ties randomly?

Code:
<?php

foreach($list as $temp_list)
{
$sort_aux[] = ($temp_list['column_to_sort_by']+(rand(1, 9)/10));
}
array_multisort($sort_aux, SORT_NUMERIC, $list);

?>

Example:

$list[]=array('name'=>'Tom', 'score'=>3);
$list[]=array('name'=>'Sam', 'score'=>3);
$list[]=array('name'=>'Joey', 'score'=>1);

Explanation:
I took an existing example found above that shows how to sort an array by one of it's columns/fields.
I just added: "+(rand(1,9)/10)" To randomly add .1 through .9 to their score to resolve the tie. (Obviously this specific example only works if you're sorting by an integer... so you may need to modify it to suit your needs.)

Hope this helps someone.

down

isp dot php at spspft dot de ¶

15 years ago

I would like to report a kind of confusion that arose with the message

Warning: Call-time pass-by-reference has been deprecated; If you would like to pass it by reference, modify the declaration of array_multisort(). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file...

from a line like this:

array_multisort (&$keyarr, &$arr );// sort against this keys

This message is not easily switched off by changing the error reporting level because it's produced at parsinig time -- not execution time.

I think this message is misleading because the arguments are passed by reference ANYWAY in array_multisort.

Anybody encountering this message should know that nothing has to be done, except deleting the ampersands (&).
I was tricked by this message because of couse I wanted to have the *sorted* array back. And couldn't find the ini file nor the declaration of array_multisort.
I think in this description of array_multisort the call by reference should be listed in the definition.

Hope this helps someone

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seiffs_at_centrum-dot-cz ¶

16 years ago

There have to be two corrections to the php_multisort($data,$keys)

    // Sort Expression
    $i=0;
    $sort='';  //here
    foreach ($keys as $k){
      if($i>0){$sort.=',';}
      $sort.='$cols[\''.$k['key'].'\']'; //and here
      if($k['sort']){$sort.=',SORT_'.strtoupper($k['sort']);}
      if($k['type']){$sort.=',SORT_'.strtoupper($k['type']);}
      $i++;
    }

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Jon L. -- intel352 [AT] gmail [DOT] com ¶

17 years ago

This is my solution for a dynamic multisort, using POST values. This doesn't account for a need to sort by multiple columns at once, but could be modified for that purpose.

<?php
/** 
    * @desc You really should validate the posted sort direction against a list of valid possibilities.
    *         Options are SORT_ASC, SORT_DESC, etc, as shown in the documentation for array_multisort
    */
$sort['direction'] = $_POST['sort_direction'] ? $_POST['sort_direction'] : 'SORT_ASC';
$sort['field']       = $_POST['sort_field'] ? $_POST['sort_field'] : 'value';

$array_to_sort = array();    
$array_to_sort['TestCase1'] = array('name'=>'Test1','value'=>'218');
$array_to_sort['TestCase2'] = array('name'=>'Test2','value'=>'10');
$array_to_sort['TestCase3'] = array('name'=>'Test3','value'=>'64');

/**
    * @desc Build columns using the values, for sorting in php
    */
$sort_arr = array();
    foreach($array_to_sort AS $uniqid => $row){
        foreach($row AS $key=>$value){
$sort_arr[$key][$uniqid] = $value;
        }
    }

    print '<b>Before sorting</b>: <br> <pre>';
print_r($array_to_sort);
    print '</pre>';

    if($sort['direction']){
array_multisort($sort_arr[$sort['field']], constant($sort['direction']), $array_to_sort);
    }

    print '<b>After sorting</b>: <br> <pre>';
print_r($array_to_sort);
    print '</pre>';

?>

This example prints out:

Before sorting:

Array
(
    [TestCase1] => Array
        (
            [name] => Test1
            [value] => 218
        )

    [TestCase2] => Array
        (
            [name] => Test2
            [value] => 10
        )

    [TestCase3] => Array
        (
            [name] => Test3
            [value] => 64
        )

)

After sorting:

Array
(
    [TestCase2] => Array
        (
            [name] => Test2
            [value] => 10
        )

    [TestCase3] => Array
        (
            [name] => Test3
            [value] => 64
        )

    [TestCase1] => Array
        (
            [name] => Test1
            [value] => 218
        )

)

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KES http://kes.net.ua ¶

18 years ago

<?
//sort by second column then first one
$orderBy=array('0'=>'desc', 'first'=>'asc');

function KES_cmp($a, $b) {
  global $orderBy;
  $result= 0;
  foreach( $orderBy as $key => $value ) {
    if( $a[$key] == $b[$key] ) continue;
    $result= ($a[$key] < $b[$key])? -1 : 1;
    if( $value=='desc' ) $result= -$result;
    break;
    }
  return $result;
  }

$result= array();
$result[]= array( 'first'=>6, 2);
$result[]= array( 'first'=>3, 2);
$result[]= array( 'first'=>1, 3);
$result[]= array( 'first'=>1, 2);
$result[]= array( 'first'=>6, 1);

print "<b>Source</b>";
print_r($result);

usort($result, 'KES_cmp');
print "<b>Result</b>";
print_r($result);
?>

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php a-t-the-r-a-t-e chir.ag ¶

18 years ago

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
        )

)

down

joao at intrasystems dot com dot br ¶

19 years ago

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
        )

)

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meddle at dzygn.com ¶

19 years ago

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
        )

)

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-1

rnacken at gmail dot com ¶

12 years ago

When I was working on a search engine, that had to order the results in PHP by multiple arguments, I got stuck on the issue of multisort erasing your (numeral) indexes for a while. Sometimes, it is important to keep these indexes intact. In my case, the indexes were IDs and the values were a percentage of how relevant the object was, considering an earlier query.
e.g: $searchResult = (23 => 0.3, 
                    102 => 0.5,
                    11 => 0.5,
                    340 => 0.5,
                    10 => 0.9);

I wanted to use array_multisort to first sort DESC on the IDs, and then on the values DESC. i.e. I wanted to show the highest values first, but in case of two (or more) objects with the same value, the higher ID would be shown first.
e.g: $searchResult = (10 => 0.9,
                   340 => 0.5,
                   102 => 0.5,
                   11 => 0.5,
                   23 => 0.3);

The easiest way to do this, I think, is:
<?php
// create a 2-deep array with the values and keys of $searchResult
$array = array(
$searchResult,
array_keys($searchResult)
    );
// use multisort, first on the values, then on the keys. This will erase the indexes in the $searchResult array
array_multisort($array[0], SORT_DESC,  $array[1], SORT_DESC);
// get the ordered keys back in the $searchResult array
$searchResult = array_combine($array[1], $array[0]);
    unset($array); //clear some memory
?>

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-2

dwalter at seznam dot cz ¶

4 years ago

My solution for multidimensional asociative array in my language, which respect all characters of alphabet
<?php
  setlocale(LC_COLLATE, 'cs_CZ.utf-8');
$prijmeni_zamestnancu = array_column($DBzamestnanci, 'prijmeni');
array_multisort($prijmeni_zamestnancu, SORT_ASC, SORT_LOCALE_STRING, $DBzamestnanci);
?>

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array_multisort

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