uksort

(PHP 4, PHP 5, PHP 7)

uksort — 使用用户自定义的比较函数对数组中的键名进行排序

说明

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

uksort() 函数将使用用户提供的比较函数对数组中的键名进行排序。如果要排序的数组需要用一种不寻常的标准进行排序，那么应该使用此函数。

参数

array: 输入的数组。
cmp_function: 在第一个参数小于，等于或大于第二个参数时，该比较函数必须相应地返回一个小于，等于或大于 0 的整数。

int callback ( mixed $a , mixed $b )

返回值

成功时返回 TRUE ，或者在失败时返回 FALSE 。

范例

Example #1 uksort() 例子

  <?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" ;
}
 ?>

以上例程会输出：

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

参见

usort() - 使用用户自定义的比较函数对数组中的值进行排序
数组排序函数对比

用户评论:

[#1] thiago at internetbudi dot com dot br [2015-10-14 19:15:56]

Sort the indices by a set order (custom order)

<?php

function sort_keys(&$array, $order) {
    uksort($array, function ($a, $b) use ($order) {
        $pos_a = array_search($a, $order);
        $pos_b = array_search($b, $order);

        if ($pos_a === false)
            return 1;
        if ($pos_b === false)
            return -1;

        return $pos_a - $pos_b;
    });

    return $array;
}

$order = ['a', 'c', 'z'];
$arr = ['a'=>1, 'b'=>2, 'c'=>3, 'f'=>4, 'z'=>5];

sort_keys($arr, $order);
// => [
//       "a" => 1,
//       "c" => 3,
//       "z" => 5,
//       "b" => 2,
//       "f" => 4
//   ]

[#2] Anonymous [2015-10-05 13:02:11]

An associative array with known keys can be easily custom sorted using a switch statement in the callback:

NB ksort can be used beforehand to ensure expected results

ksort($array);

uksort($array, function ($a) {
switch($a) {
case 'pepperoni':
return 0;
case 'beef':
return 1;
case 'chicken':
return 2;
case 'ham':
return 3;
case 'vegetarian':
return 4;
}
});

[#3] PHPUser [2015-02-06 17:32:19]

[Editor's note: the following comment may be factually incorrect]

uksort is only usable in the UK
<?php if($country=="UK"){ uksort(); }else{ echo "You have to live in UK to use uksort()."; } ?>

[#4] ingo at example dot test [2014-05-05 13:30:40]

sort with collation, to have umlauts correctly:

uksort($retval, array(Collator::create( 'de_DE' ), 'compare'));

[#5] mdsky at web dot de [2010-05-23 11:26:49]

Case insensitive without own function:

uksort($array, "strnatcasecmp");

[#6] contacto at hardcode dot com dot ar [2009-07-29 06:56:29]

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"); ?>

[#7] brian dot short at gmail dot com [2009-07-07 07:58:15]

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
)

[#8] Jimomighty [2005-03-19 19:30:37]

...

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 );

...

[#9] aleczapka at gmx dot net [2004-12-22 04:35:31]

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; ... ?>

[#10] jg at delegation dot ca [2004-12-17 07:41:47]

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;
}

[#11] aleczapka at gmx dot net [2004-12-06 04:27:45]

[#12] fabriceb at gmx dot net [2004-07-08 06:26:23]

(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.

[#13] webmaster at kik-it at N0SP4M dot com [2004-02-09 10:03:25]

The code below allows you to sort an array_A following array_B keys order, original keys and values remain associated.

<?php //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)

[#14] guss at typo dot co dot il [2003-12-07 12:18:26]

[#15] ignatius dot reilly at free dot fr [2003-11-13 10:59:13]

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 ) ;

[#16] pachollini at stones dot com [2003-03-03 04:47:10]

[#17] kumar at chicagomodular (dot) com [2003-01-29 21:12:37]

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