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krsort

Last updated: Fri, 24 Jul 2009

ksort

(PHP 4, PHP 5)

ksort — 키에 의한 배열 정렬

설명

bool ksort ( array &$array [, int $sort_flags ] )

키에 의해 배열을 정렬하고, 키와 데이터의 연관성을 유지한다. 이 함수는 주로 연관 배열에 유용하다.

인수

array: 입력 배열.
sort_flags: 선택적인 sort_flags 인수로 정렬 방법을 바꿀 수 있습니다. 자세한 내용은 sort()를 참고하십시오.

반환값

성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.

변경점

버전	설명
4.0.0	선택적인 `sort_flags` 인수 추가.

예제

Example #1 ksort() 예제


<?php
$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
ksort($fruits);
foreach ($fruits as $key => $val) {
    echo "$key = $val\n";
}
?>

위 예제의 출력:

a = orange
b = banana
c = apple
d = lemon

참고

asort() - 배열을 정렬하고 인덱스 상관 관계를 유지
arsort() - 배열을 내림차순 정렬하고 인덱스의 상관관계를 유지
krsort() - 키에 의한 배열 역순 정렬
uksort() - 사용자 정의 비교 함수를 사용하여 키에 의한 배열 정렬
sort() - 배열 정렬
natsort() - "자연순" 알고리즘으로 배열 정렬
rsort() - 역순으로 배열 정렬

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krsort

Last updated: Fri, 24 Jul 2009

add a note User Contributed Notes
ksort

DavidG
17-Jun-2010 11:17


A nice way to do sorting of a key on a multi-dimensional array without having to know what keys you have in the array first:





<?php


$people = array(


array("name"=>"Bob","age"=>8,"colour"=>"red"),


array("name"=>"Greg","age"=>12,"colour"=>"blue"),


array("name"=>"Andy","age"=>5,"colour"=>"purple"));





var_dump($people);





$sortArray = array();





foreach($people as $person){


    foreach($person as $key=>$value){


        if(!isset($sortArray[$key])){


            $sortArray[$key] = array();


        }


        $sortArray[$key][] = $value;


    }


}





$orderby = "name"; //change this to whatever key you want from the array





array_multisort($sortArray[$orderby],SORT_DESC,$people);





var_dump($people);


?>





Output from first var_dump:





[0]=&gt;


  array(3) {


    ["name"]=&gt;


    string(3) "Bob"


    ["age"]=&gt;


    int(8)


    ["colour"]=&gt;


    string(3) "red"


  }


  [1]=&gt;


  array(3) {


    ["name"]=&gt;





    string(4) "Greg"


    ["age"]=&gt;


    int(12)


    ["colour"]=&gt;


    string(4) "blue"


  }


  [2]=&gt;


  array(3) {


    ["name"]=&gt;


    string(4) "Andy"


    ["age"]=&gt;


    int(5)


    ["colour"]=&gt;





    string(6) "purple"


  }


}





Output from 2nd var_dump:





array(3) {


  [0]=&gt;


  array(3) {


    ["name"]=&gt;


    string(4) "Greg"


    ["age"]=&gt;


    int(12)


    ["colour"]=&gt;


    string(4) "blue"


  }


  [1]=&gt;


  array(3) {


    ["name"]=&gt;





    string(3) "Bob"


    ["age"]=&gt;


    int(8)


    ["colour"]=&gt;


    string(3) "red"


  }


  [2]=&gt;


  array(3) {


    ["name"]=&gt;


    string(4) "Andy"


    ["age"]=&gt;


    int(5)


    ["colour"]=&gt;





    string(6) "purple"


  }





There's no checking on whether your array keys exist, or the array data you are searching on is actually there, but easy enough to add.

serpro at gmail dot com
13-Mar-2009 08:32


Here is a function to sort an array by the key of his sub-array.



<?php



function sksort(&$array, $subkey="id", $sort_ascending=false) {



    if (count($array))

        $temp_array[key($array)] = array_shift($array);



    foreach($array as $key => $val){

        $offset = 0;

        $found = false;

        foreach($temp_array as $tmp_key => $tmp_val)

        {

            if(!$found and strtolower($val[$subkey]) > strtolower($tmp_val[$subkey]))

            {

                $temp_array = array_merge(    (array)array_slice($temp_array,0,$offset),

                                            array($key => $val),

                                            array_slice($temp_array,$offset)

                                          );

                $found = true;

            }

            $offset++;

        }

        if(!$found) $temp_array = array_merge($temp_array, array($key => $val));

    }



    if ($sort_ascending) $array = array_reverse($temp_array);



    else $array = $temp_array;

}



?>



Example

<?php

$info = array("peter" => array("age" => 21,

                                           "gender" => "male"

                                           ),

                   "john"  => array("age" => 19,

                                           "gender" => "male"

                                           ),

                   "mary" => array("age" => 20,

                                           "gender" => "female"

                                          )

                  );



sksort($info, "age");

var_dump($info);



sksort($info, "age", true);

var_dump($ifno);

?>



This will be the output of the example:



/*DESCENDING SORT*/

array(3) {

  ["peter"]=>

  array(2) {

    ["age"]=>

    int(21)

    ["gender"]=>

    string(4) "male"

  }

  ["mary"]=>

  array(2) {

    ["age"]=>

    int(20)

    ["gender"]=>

    string(6) "female"

  }

  ["john"]=>

  array(2) {

    ["age"]=>

    int(19)

    ["gender"]=>

    string(4) "male"

  }

}



/*ASCENDING SORT*/

array(3) {

  ["john"]=>

  array(2) {

    ["age"]=>

    int(19)

    ["gender"]=>

    string(4) "male"

  }

  ["mary"]=>

  array(2) {

    ["age"]=>

    int(20)

    ["gender"]=>

    string(6) "female"

  }

  ["peter"]=>

  array(2) {

    ["age"]=>

    int(21)

    ["gender"]=>

    string(4) "male"

  }

}

maik dot riechert at animey dot net
13-Aug-2008 04:02


Be careful when using ksort for mixed type keys!!



$a = array(

    'first' => true,

    0       => 'sally',

);



$b = array(

    0       => 'sally',

    'first' => true,

);



ksort($a);

ksort($b);

var_dump($a);

var_dump($b);



Output is:

array(

    0 => 'sally',

    'first' => true,

)



array(

    'first' => true,

    0 => 'sally',

)



If you want same results for both arrays, use:



ksort($a, SORT_STRING);



The reason for that lays in the compare mechanism which would normally just typecast 'first' to an integer or 0 to a string when comparing it to each other. So you have to use SORT_STRING, otherwise you would lose information when 'first' is converted to int.

06-Nov-2006 11:56


Why not just use built-in PHP functions? You can do an in-place natural sort by keys with:



uksort($array, 'strnatcasecmp');

richard dot quadling at bandvulc dot co dot uk
24-Oct-2005 05:40


Just to complete the comments made by ssb45.



If the supplied array is an empty array, the value returned is NOT an array.



All that is required is to pre-initialize the result.



function natksort(&$aToBeSorted)

    {

    $aResult = array();

    $aKeys = array_keys($aToBeSorted);

    natcasesort($aKeys);

    foreach ($aKeys as $sKey)

        {

        $aResult[$sKey] = $aToBeSorted[$sKey];

        }

    $aToBeSorted = $aResult;

    return True;

    }

ssb45 at cornell dot edu
30-Jun-2005 09:28


The function that justin at booleangate dot org provides works well, but be aware that it is not a drop-in replacement for ksort as is.  While ksort sorts the array by reference and returns a status boolean, natksort returns the sorted array, leaving the original untouched.  Thus, you must use this syntax:



$array = natksort($array);



If you want to use the more natural syntax:



$status = natksort($array);



Then use this modified version:



function natksort(&$array) {

    $keys = array_keys($array);

    natcasesort($keys);



    foreach ($keys as $k) {

        $new_array[$k] = $array[$k];

    }



    $array = $new_array;

    return true;

}

justin at booleangate dot org
18-Jan-2005 07:34


Here's a handy function for natural order sorting on keys.



function natksort($array) {

  // Like ksort but uses natural sort instead

  $keys = array_keys($array);

  natsort($keys);



  foreach ($keys as $k)

    $new_array[$k] = $array[$k];



  return $new_array;

}

yaroukh at email dot cz
07-May-2004 12:38


I believe documentation should mention which of array-functions do reset the internal pointer; this one does so ...

pedromartinez at alquimiapaginas dot com
29-Nov-2003 02:28


A list of directories can be listed sorted by date (newer first) with this script. This is usefull if the directories contain (for example) pictures and you want the newer to appear first.



$maindir = "." ;

$mydir = opendir($maindir) ;



// SORT

$directorios = array();

while (false !== ($fn = readdir($mydir)))

{

    if (is_dir($fn) && $fn != "." && $fn != "..") 

    {

        $directory = getcwd()."/$fn";

        $key = date("Y\-m\-d\-His ", filectime($directory));

        $directorios[$key] = $directory;

    }

}



ksort($directorios);

$cronosdir = array();

$cronosdir = array_reverse($directorios);



while (list($key, $directory) = each($cronosdir)) {

    echo "$key = $directory<bR>";

}



Pedro

10-Mar-2002 01:39


here 2 functions to ksort/uksort an array and all its member arrays



function tksort(&$array)

  {

  ksort($array);

  foreach(array_keys($array) as $k)

    {

    if(gettype($array[$k])=="array")

      {

      tksort($array[$k]);

      }

    }

  }



function utksort(&$array, $function)

  {

  uksort($array, $function);

  foreach(array_keys($array) as $k)

    {

    if(gettype($array[$k])=="array")

      {

      utksort($array[$k], $function);

      }

    }

  }

delvach at mail dot com
07-Nov-2001 07:59


A real quick way to do a case-insensitive sort of an array keyed by strings:





uksort($myArray, "strnatcasecmp");

sbarnum at mac dot com
20-Oct-2001 08:24


ksort on an array with negative integers as keys yields some odd results.  Not sure if this is a bad idea (negative key values) or what.

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krsort

Last updated: Fri, 24 Jul 2009