PHP 5.4.33 Released

uksort

(PHP 4, PHP 5)

uksortSort an array by keys using a user-defined comparison function

Descrierea

bool uksort ( array &$array , callable $key_compare_func )

uksort() will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.

Parametri

array

The input array.

key_compare_func

Funcția de comparare trebuie să întoarcă un întreg mai mic, egal cu sau mai mare decât zero dacă primul argument este considerat respectiv mai mic, egal cu sau mai mare decât al doilea argument.

int callback ( mixed $a, mixed $b )

Valorile întoarse

Întoarce valoarea TRUE în cazul succesului sau FALSE în cazul eșecului.

Exemple

Example #1 uksort() example

<?php
function cmp($a$b)
{
    
$a preg_replace('@^(a|an|the) @'''$a);
    
$b preg_replace('@^(a|an|the) @'''$b);
    return 
strcasecmp($a$b);
}

$a = array("John" => 1"the Earth" => 2"an apple" => 3"a banana" => 4);

uksort($a"cmp");

foreach (
$a as $key => $value) {
    echo 
"$key$value\n";
}
?>

Exemplul de mai sus va afișa:

an apple: 3
a banana: 4
the Earth: 2
John: 1

Vedeți de asemenea

add a note add a note

User Contributed Notes 14 notes

up
5
contacto at hardcode dot com dot ar
5 years ago
need a case insensitive sort by key function? i did and couldn find it, so:

<?php
function insensitive_uksort($a,$b) {
    return
strtolower($a)<strtolower($b);
}
uksort($arr, "insensitive_uksort");
?>
up
3
fabriceb at gmx dot net
10 years ago
(about sorting an array of objects by their properties in a class - inspired by webmaster at zeroweb dot org at usort function)
I'm using classes as an abstraction for querying records in a database and use arrays of objects to store records that have an 1 to n relationship. E.g. a class "family" has family members stored as an array of objects. Each of those objects prepresents a record in a database related to the family (by it's familyId).

To identify members, I'm using their memberId as the key of the array e.g. $family->members[$memberId].
To sort the family members AFTER fetching them with the database query, you can use the functions _objSort and sortMembers which will sort the "members" array by key using it's properties (for space reasons I didn't include the methods used to open the records):
<?php
class familyMember
{
    var
$memberId;
    var
$familyId;
    var
$firstName;
    var
$age;
    var
$hairColor;
// ...
}

class
family
{
    var
$familyId;
    var
$name;
    var
$members = array(); // array of familyMember objects
   
var $sortFields = array();
    var
$sortDirections = array();
   
// ...
   
function _objSort(&$a, &$b, $i = 0)
    {
       
$field        = $this->sortFields[$i];
       
$direction    = $this->sortDirections[$i];
       
       
$diff = strnatcmp($this->details[$a]->$field, $this->details[$b]->$field) * $direction;
        if (
$diff == 0 && isset($this->sortFields[++$i]))
        {
           
$diff = $this->_objSort($a, $b, $i);
        }
       
        return
$diff;
    }
   
    function
sortMembers($sortFields)
    {
       
$i = 0;
        foreach (
$sortFields as $field => $direction)
        {
           
$this->sortFields[$i] = $field;
           
$direction == "DESC" ? $this->sortDirections[$i] = -1 : $this->sortDirections[$i] = 1;
           
$i++;
        }
       
       
uksort($this->details, array($this, "_objSort"));
       
       
$this->sortFields = array();
       
$this->sortDirections = array();
    }
}
// open a family
$familyId = 5;
$family = new family($familyId);
$family->open(); // this will also fetch all members

// sort members by 3 fields
$family->sortMembers(array("firstName" => "ASC", "age" => "DESC", "hairColor" => "ASC"));
// output all family members
foreach ($family->members as $member)
{
    echo
$member->firstName." - ".$member->age." - ".$member->hairColor."<br />";
}
?>

Note that this might not be the fastest thing on earth and it hasn't been tested very much yet but I hope it's useful for someone.
up
3
webmaster at kik-it at N0SP4M dot com
10 years ago
The code below allows you to sort an array_A following array_B keys order, original keys and values remain associated.

<?

//main function
Function SortArrayAKeysLikeArrayBKeys(&$TheArrayToSort){
  
uksort($TheArrayToSort,"SortArrayAKeysLikeArrayBKeys_cmp");
}

//the custom compare function
Function SortArrayAKeysLikeArrayBKeys_cmp($a,$b){
  global
$TheArrayOrder;
 
$PosA=KeyPosInArray($a,$TheArrayOrder);
 
$PosB=KeyPosInArray($b,$TheArrayOrder);
  if (
$PosA==$PosB){return 0;}else{return ($PosA > $PosB ? 1 : -1);}
}

//where is my key in my array
Function KeyPosInArray($Key,$Array){
  
$i=0;
  
$Pos=99999999;
   if(
$Array){
      foreach(
$Array as $K => $V){
        
$i++;
         if(
$K==$Key){
           
$Pos=$i;
            break;
         }
      }
   }
   return
$Pos;
}

//the array you want to sort
$AnyArrayToSort['age']='19';
$AnyArrayToSort['ville']='rennes';
$AnyArrayToSort['website']='kik-it.com';
$AnyArrayToSort['region']='bretagne';
$AnyArrayToSort['code_postal']='35200';
$AnyArrayToSort['Nom']='Fred';

//the array with the correct keys/values order
$TheArrayOrder['Nom']='Whatever';
$TheArrayOrder['age']='Anything';
$TheArrayOrder['region']='What u want';
$TheArrayOrder['ville']='Something';
$TheArrayOrder['code_postal']='Nothing';

//before sort
print_r($AnyArrayToSort);   
echo
"<br>";
//we sort
SortArrayAKeysLikeArrayBKeys($AnyArrayToSort);
echo
"<br>";
//after sort
print_r($AnyArrayToSort);
?>

Will print :

Array ( [age] => 19 [ville] => rennes [website] => kik-it.com [region] => bretagne [code_postal] => 35200 [Nom] => Fred )

Array ( [Nom] => Fred [age] => 19 [region] => bretagne [ville] => rennes [code_postal] => 35200 [website] => kik-it.com )

The keys not listed in the $TheArrayOrder will appear at the end of your sorted array (only if Key Pos < 99999999 ;o)
up
2
mdsky at web dot de
4 years ago
Case insensitive without own function:

uksort($array, "strnatcasecmp");
up
1
brian dot short at gmail dot com
5 years ago
If you need to periodically sort by grades (A, A+, D-, etc.), here is a compare function that compares strings by the case-insensitive method, unless it finds a grade, in which case it correctly sorts by putting "plus" grades first, unmarked grades second, and "minus" grades last.

<?php
function cmp($a, $b)
{
  
$a = preg_replace('@^(a|an|the) @', '', $a);
  
$b = preg_replace('@^(a|an|the) @', '', $b);

  
//special code for grades
  
if (strpos( $a, "+") !== false || strpos( $b, "+") !== false  ||
      
strpos( $a, "-") !== false || strpos( $b, "-") !== false ){

       
$substrA = substr($a, 0, 1);
       
$substrB = substr($b, 0, 1);       

       
$modifierA = (strlen($a) == 2) ? substr($a, 1, 1) : "";
       
$modifierB = (strlen($b) == 2) ? substr($b, 1, 1) : "";
   
        if (
$substrA == $substrB){
           
//figure out plusses and minuses.
           
if ($modifierA == "+"){
                return -
1;
            } else if (
$modifierB == "+"){
                return
1;
            }
       
            if (
$modifierA == "-"){
                return
1;
            } else if (
$modifierB == '-'){
                return -
1;
            }
        } else {
            return
strcasecmp($a, $b);
        }

    }
   return
strcasecmp($a, $b);
}

$grades = array(
                
"C+" => 13    ,
               
"C" => 10     ,
               
"D+" => 8     ,
               
"B+" => 7     ,
               
"C-" => 6     ,
               
"A-" => 5     ,
               
"F" => 5      ,
               
"B" => 4      ,
               
"B-" => 4     ,
               
"D" => 3      ,
               
"D-" => 3     ,
               
"A+" => 1
   
);

uksort($grades, "cmp");
?>

result:  Array
(
    [A+] => 1
    [A-] => 5
    [B+] => 7
    [B] => 4
    [B-] => 4
    [C+] => 13
    [C] => 10
    [C-] => 6
    [D+] => 8
    [D] => 3
    [D-] => 3
    [F] => 5
)
up
1
aleczapka at gmx dot net
9 years ago
One remark regarding array_sorter class.
It won't work correctly with eg. dates from mysql like 20041206105350, cause you can't convert such number into integer. To fix it remove intval() from the code. If the variable is a number it will work without converting this to int anyways. Here is the fix.

<?php
....
if (
$a == $b)
    return
0;
if (
$this->sasc)
    return (
$a > $b) ? 1 : -1;
else
    return (
$a > $b) ? -1 : 1;
...
?>
up
1
jg at delegation dot ca
9 years ago
To sort dates with uksort:

function datediff($a, $b) {
   

$a = date('U',$a);
$b = date('U',$b);

if ($a == $b) $r = 0;
else $r = ($a > $b) ? 1: -1;

return $r;
}
up
1
guss at typo dot co dot il
10 years ago
Regarding the recursive sorting function above:
Genrally speaking, any recursion can be reimplemented using simple iteration. in the specific case, using recursion to compare strings has a huge performance impact while a simple loop would suffice and be faster and more simple.
Recursion is only good if it simplifies your code or your understanding of the concept. the previous example does neither, especially as it does a lot of repetitive things in each iteration, such as asigning the character order constant, rebuilding it into an array and such

For example, the string comparison could be written as such :
function str_compare($a,$b) {
    $order="aAbBcC&#269;&#268;..."; // longer normally & without that html entities
    $default = strlen($a) - strlen($b);
    $minlen = strlen($a) < strlen($b) ? strlen($a) : strlen($b);
    for ($i = 0; $i < $minlen; $i++) {
        $pos_a=strpos($order,$a[$i]);
        $pos_b=strpos($order,$b[$i]);
        if ($pos_a != $pos_b)
            return $pos_a - $pos_b;
    }
    return $default;
}

Which is much simpler and faster.
Note that the above function will break for characters that are not listed in $order. it should be failry trivial to fix it.
up
1
ignatius dot reilly at free dot fr
10 years ago
To use a more complicated comparison function, one can use a callback to a method of an object instance.
For example the following will take an array $arr whose keys are the same as those of $reference, and reorder $arr so that the keys appear in the same order as in $reference.

class kcmp {
    var $reference ;
    function kcmp( $reference ) {
       $this->reference = $reference ;
    }
    function kcompare( $a, $b ) {
       $keys = array_keys( $this->reference ) ;
       $position_a = array_search( $a, $keys ) ;
       $position_b = array_search( $b, $keys ) ;
       return  $position_a < $position_b ? -1 : 1 ;   
    }
}

$reference = array(
    "k2" => "a2",
    "k3" => "a3",
    "k1" => "a1"
) ;
$arr = array(
    "k1" => "b1",
    "k2" => "b2",
    "k3" => "b3"
) ;
print_r( $arr ) ;
uksort( $arr, array( new kcmp( $reference ), "kcompare" ) ) ;
print_r( $arr ) ;
up
1
kumar at chicagomodular (dot) com
11 years ago
The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.
--necessary info from http://www.php.net/manual/en/function.usort.php if you didn't see it already
up
2
Jimomighty
9 years ago
...

function cmp($a, $b)
{
   if ($a == $b) {
       return 0;
   }
   return ($a < $b) ? -1 : 1;
}

function uksort_tree ( &$array )
{
    // [PHP5] foreach ( $array as &$value )
    foreach ( $array as $key => $value )
    {
       if ( is_array ( $value ) )
       {
            // [PHP5] uksort_tree ( $value );
           uksort_tree ( $array[$key] );
       }
    }

    uksort( $array, "cmp" );
}

uksort_tree( $myEntryArray );

...
up
1
aleczapka at gmx dot net
9 years ago
Here is a small and very fast object to handle sorting of multidimentional arrays by a key.
<?php
/**
* Handles multidimentional array sorting by a key (not recursive)
*
* @author Oliwier Ptak <aleczapka at gmx dot net>
*/
class array_sorter
{
    var
$skey = false;
    var
$sarray = false;
    var
$sasc = true;

   
/**
    * Constructor
    *
    * @access public
    * @param mixed $array array to sort
    * @param string $key array key to sort by
    * @param boolean $asc sort order (ascending or descending)
    */
   
function array_sorter(&$array, $key, $asc=true)
    {
       
$this->sarray = $array;
       
$this->skey = $key;
       
$this->sasc = $asc;
    }

   
/**
    * Sort method
    *
    * @access public
    * @param boolean $remap if true reindex the array to rewrite indexes
    */
   
function sortit($remap=true)
    {
       
$array = &$this->sarray;
       
uksort($array, array($this, "_as_cmp"));
        if (
$remap)
        {
           
$tmp = array();
            while (list(
$id, $data) = each($array))
               
$tmp[] = $data;
            return
$tmp;
        }
        return
$array;
    }

   
/**
    * Custom sort function
    *
    * @access private
    * @param mixed $a an array entry
    * @param mixed $b an array entry
    */
   
function _as_cmp($a, $b)
    {
       
//since uksort will pass here only indexes get real values from our array
       
if (!is_array($a) && !is_array($b))
        {
           
$a = $this->sarray[$a][$this->skey];
           
$b = $this->sarray[$b][$this->skey];
        }

       
//if string - use string comparision
       
if (!ctype_digit($a) && !ctype_digit($b))
        {
            if (
$this->sasc)
                return
strcasecmp($a, $b);
            else
                return
strcasecmp($b, $a);
        }
        else
        {
            if (
intval($a) == intval($b))
                return
0;

            if (
$this->sasc)
                return (
intval($a) > intval($b)) ? -1 : 1;
            else
                return (
intval($a) > intval($b)) ? 1 : -1;
        }
    }

}
//end of class
?>

Sample $input_array:

Array
(
    [0] => Array
        (
            [id] => 961
            [uid] => 29
            [gid] => 12
            [parent_id] => 147
            [created] => 20041206105350
            [modified] => 20041206110702
        )

    [1] => Array
        (
            [id] => 41
            [uid] => 29
            [gid] => 12
            [parent_id] => 153
            [created] => 20041025154009
            [modified] => 20041206105532
        )

    [2] => Array
        (
            [id] => 703
            [uid] => 29
            [gid] => 12
            [parent_id] => 419
            [created] => 20041025154132
            [modified] => 20041027150259
        )

Example of usage:
<?php
   
function multi_sort(&$array, $key, $asc=true)
    {
       
$sorter = new array_sorter($array, $key, $asc);
        return
$sorter->sortit();
    }
   
//sort by parent_id in descending order
   
$my_array = multi_sort($input_array, "parent_id", false);
?>

The result array will be:
Array
(

    [0] => Array
        (
            [id] => 703
            [uid] => 29
            [gid] => 12
            [parent_id] => 419
            [created] => 20041025154132
            [modified] => 20041027150259
        )

    [1] => Array
        (
            [id] => 41
            [uid] => 29
            [gid] => 12
            [parent_id] => 153
            [created] => 20041025154009
            [modified] => 20041206105532
        )

    [2] => Array
        (
            [id] => 961
            [uid] => 29
            [gid] => 12
            [parent_id] => 147
            [created] => 20041206105350
            [modified] => 20041206110702
        )
up
2
ingo at example dot test
4 months ago
sort with collation, to have umlauts correctly:

uksort($retval, array(Collator::create( 'de_DE' ), 'compare'));
up
-2
pachollini at stones dot com
11 years ago
I tried to write my own function for sorting with special Czech characters, which php normally compares wrong way. The function is recoursive, it compares the first characters of the strings and when they're the same, the function calls itself with parameters without the first character. My php often crashed by calling this function. After some time if found the problem: it crashed after 10th recoursive call. I think it's a bug in php, and I've made this workaround:

function str_compare($a,$b,$level=0)
    {
    $maxlevel=9;
    if($GLOBALS["STR_COMPARE"] && is_array($a))
        {
        $a=$a[$GLOBALS["STR_COMPARE"]];
        $b=$b[$GLOBALS["STR_COMPARE"]];
        }
    $result=0;
    if($a==$b) return 0;
    elseif($a=="") return ($b=="") ? 0 : 1;
    elseif ($b=="") return -1;
    else
        {
        $order="aAbBcC&#269;&#268;..."; // longer normally & without that html entities
        for($i=0;$i<strlen($order);$i++) $codes[]=ord($order[$i]);
        $char_a=$a[0];$char_b=$b[0];
        $pos_a=array_search(ord($a),$codes); $pos_b=array_search(ord($b),$codes);
        //echo"$char_a - $pos_a<br>";
        if($pos_a===false || $pos_b===false)
            {
            if($char_a==$char_b)
                {
                if ($level<=$maxlevel) $result=str_compare (substr($a,1),substr($b,1),$level+1);
                else $a<$b ? $result=-1 : $result=1;
                }
            else ($char_a<$char_b) ? $result=-1 : $result=1;
            }
        else
            {
            if($pos_a==$pos_b)
                {
                if ($level<=$maxlevel) $result=str_compare(substr($a,1), substr($b,1),$level+1);
                else $a<$b ? $result=-1 : $result=1;
                }
            else ($pos_a<$pos_b) ? $result=-1 : $result=1;
            }
        return $result;
        }
    }
To Top