sort

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

sort — 对数组升序排序

说明

sort ( array &$array , int $flags = SORT_REGULAR ) : bool

本函数对数组按照升序进行排序。

Note:
如果两个成员完全相同，那么它们在排序数组中的相对顺序是未定义的。

参数

array

输入的数组。

flags

可选的第二个参数 flags 可以用以下值改变排序的行为：

排序类型标记：

SORT_REGULAR - 正常比较单元详细描述参见比较运算符章节
SORT_NUMERIC - 单元被作为数字来比较
SORT_STRING - 单元被作为字符串来比较
SORT_LOCALE_STRING - 根据当前的区域（locale）设置来把单元当作字符串比较，可以用 setlocale() 来改变。
SORT_NATURAL - 和 natsort() 类似对每个单元以"自然的顺序"对字符串进行排序。
SORT_FLAG_CASE - 能够与 SORT_STRING 或 SORT_NATURAL 合并（OR 位运算），不区分大小写排序字符串。

返回值

成功时返回 true，或者在失败时返回 false。

范例

Example #1 sort() 例子


<?php

$fruits = array("lemon", "orange", "banana", "apple");
sort($fruits);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}

?>

以上例程会输出：

fruits[0] = apple
fruits[1] = banana
fruits[2] = lemon
fruits[3] = orange

fruits 被按照字母顺序排序。

Example #2 使用 sort() 不区分大小写自然排序的例子


<?php

$fruits = array(
    "Orange1", "orange2", "Orange3", "orange20"
);
sort($fruits, SORT_NATURAL | SORT_FLAG_CASE);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}

?>

以上例程会输出：

fruits[0] = Orange1
fruits[1] = orange2
fruits[2] = Orange3
fruits[3] = orange20

fruits 排序得像 natcasesort() 的结果。

注释

Note: 此函数为 array 中的元素赋与新的键名。这将删除原有的键名，而不是仅仅将键名重新排序。

Note: 和大多数 PHP 排序函数一样，sort() 使用了 » Quicksort 实现的。 The pivot is chosen in the middle of the partition resulting in an optimal time for already sorted arrays. This is however an implementation detail you shouldn't rely on.

Warning

在对含有混合类型值的数组以 flags 为 SORT_REGULAR 排序时要小心，因为 sort() 可能会产生不可预知的结果。

参见

asort() - 对数组进行升序排序并保持索引关系
rsort() - 对数组降序排序
数组排序函数对比

User Contributed Notes

aminkhoshzahmat at gmail dot com 01-Jun-2020 07:02


Let's say we have a list of names, and it is not sorted.



<?php



$names = array('Amin', 'amir', 'sarah', 'Somayeh', 'armita', 'Armin');



sort($names); // simple alphabetical sort

print_r($names);

?>

Result is :

Array

(

    [0] => Amin

    [1] => Armin

    [2] => Somayeh // actually it's not sort alphabetically from here!

    [3] => amir         // comparison is based on ASCII values.

    [4] => armita

    [5] => sarah

)



If you want to sort alphabeticaly no matter it is upper or lower case:



<?php



sort($names, SORT_STRING | SORT_FLAG_CASE);

print_r($names);

?>



Result is:

Array

(

    [0] => Amin

    [1] => amir

    [2] => Armin

    [3] => armita

    [4] => sarah

    [5] => Somayeh

)

Md. Abutaleb 25-Feb-2020 12:28


<?php 

/*

As I found the sort() function normally works as ascending order based on the following priority :

1. NULL

2. Empty 

3. Boolean FALSE 

4. String 

5. Float 

6. Int 

7. Array

8. Object 



Consider the following array: 

*/



$a = ['fruit'=> 'apple', 'A' => 10, 20, 5, 2.5, 5=>'A new value', 'last' => 'value', TRUE, NULL, "", FALSE, array(), new StdClass];

sort($a);

var_dump($a);



#The output is: 



array(13) {

  [0]=>NULL

  [1]=> string(0) ""

  [2]=>bool(false)

  [3]=>string(11) "A new value"

  [4]=>string(5) "apple"

  [5]=>string(5) "value"

  [6]=> float(2.5)

  [7]=> int(5)

  [8]=>int(10)

  [9]=>int(20)

  [10]=>array(0) { }

  [11]=> bool(true)

  [12]=>object(stdClass)#1 (0) {}

}



//Hope it will remove your confusion when you're sorting an array with mix type data. 

?>

r at rcse dot de 23-Dec-2018 10:15


Here is no word about sorting UTF-8 strings by any collation. This should not be so uncommon?

Abhishek Banerjee 08-Jun-2016 07:39

aditycse at gmail dot com 07-Aug-2015 10:34


/*

 * Name : Aditya Mehrotra 

 * Email: aditycse@gmail.com

 */

//Example for sorting by values for an alphanumeric array also having case-sensitive data

$exampleArray1 = $exampleArray2 = array(

    0 => 'example1',

    1 => 'Example10',

    2 => 'example12',

    3 => 'Example2',

    4 => 'example3',

    5 => 'EXAMPLE10',

    6 => 'example10'

);



//default sorting

asort($exampleArray1);



// alphanumeric with case-sensitive data sorting by values

asort($exampleArray2, SORT_STRING | SORT_FLAG_CASE | SORT_NATURAL);



//output of defaut sorting

print_r($exampleArray1);

/*

 * output of default sorting

  Array

  (

  [5] => EXAMPLE10

  [1] => Example10

  [3] => Example2

  [0] => example1

  [6] => example10

  [2] => example12

  [4] => example3

  )

 */



print_r($exampleArray2);

/*

 * output of alphanumeric with case-sensitive data sorting by values

 Array

(

    [0] => example1

    [3] => Example2

    [4] => example3

    [5] => EXAMPLE10

    [1] => Example10

    [6] => example10

    [2] => example12

)

 */

williamprogphp at[pleaseNOTSPAM] yahoo d 20-Dec-2013 12:15


In order to make some multidimensional quick sort implementation, take advantage of this stuff



<?php

        function quickSortMultiDimensional($array, $chave) {

            if( count( $array ) < 2 ) {

                return $array;

            }

            $left = $right = array( );

            reset( $array );

            $pivot_key    = key( $array );

            $pivot    = array_shift( $array );

            foreach( $array as $k => $v ) {

                if( $v[$chave] < $pivot[$chave] )

                        $left[$k][$chave] = $v[$chave];

                else

                        $right[$k][$chave] = $v[$chave];

            }

            return array_merge(

                                    quickSortMultiDimensional($left, $chave), 

                                    array($pivot_key => $pivot), 

                                    quickSortMultiDimensional($right, $chave)

            );            

        }

?>



I make it using the idea from pageconfig dot com



tks for viewing

me[ at ]szczepan[ dot ]info 27-Dec-2012 12:36


Sorting the keys, but keep the values in order is not possible by just ordering, because it would result in a new array. This is also the solution: Create a new array



<?php

$a = array(9=>"a",8=>"c",5=>"d");



$keys = array_keys($a);

sort($keys);

$result = array_combine($keys, array_values($a));



//Result : array(5=>"a",8=>"c",9=>"d");

?>

Walter Tross 16-Dec-2011 02:38


unless you specify the second argument, "regular" comparisons will be used. I quote from the page on comparison operators:

"If you compare a number with a string or the comparison involves numerical strings, then each string is converted to a number and the comparison performed numerically."

What this means is that "10" < "1a", and "1a" < "2", but "10" > "2". In other words, regular PHP string comparisons are not transitive.

This implies that the output of sort() can in rare cases depend on the order of the input array:

<?php

function echo_sorted($a)

{

   echo "{$a[0]} {$a[1]} {$a[2]}";

   sort($a);

   echo " => {$a[0]} {$a[1]} {$a[2]}\n";

}

// on PHP 5.2.6:

echo_sorted(array( "10", "1a", "2")); // => 10 1a 2

echo_sorted(array( "10", "2", "1a")); // => 1a 2 10

echo_sorted(array( "1a", "10", "2")); // => 2 10 1a

echo_sorted(array( "1a", "2", "10")); // => 1a 2 10

echo_sorted(array( "2", "10", "1a")); // => 2 10 1a

echo_sorted(array( "2", "1a", "10")); // => 10 1a 2

?>

ajanata at gmail dot com 20-Oct-2011 09:13


This took me longer than it should have to figure out, but if you want the behavior of sort($array, SORT_STRING) (that is, re-indexing the array unlike natcasesort) in a case-insensitive manner, it is a simple matter of doing usort($array, strcasecmp).

alex dot hristov dot 88 at gmail dot com 16-Jun-2011 07:26


As some people have mentioned before sorting a multidimentional array can be a bit tricky. it took me quite a while to get it going but it works as a charm:



<?php

//$order has to be either asc or desc

 function sortmulti ($array, $index, $order, $natsort=FALSE, $case_sensitive=FALSE) {

        if(is_array($array) && count($array)>0) {

            foreach(array_keys($array) as $key) 

            $temp[$key]=$array[$key][$index];

            if(!$natsort) {

                if ($order=='asc')

                    asort($temp);

                else    

                    arsort($temp);

            }

            else 

            {

                if ($case_sensitive===true)

                    natsort($temp);

                else

                    natcasesort($temp);

            if($order!='asc') 

                $temp=array_reverse($temp,TRUE);

            }

            foreach(array_keys($temp) as $key) 

                if (is_numeric($key))

                    $sorted[]=$array[$key];

                else    

                    $sorted[$key]=$array[$key];

            return $sorted;

        }

    return $sorted;

}

?>

cmarshall at gmx dot de 17-May-2011 03:10


I read up on various problems re: sort() and German Umlaut chars and my head was soon spinning - bug in sort() or not, solution via locale or not, etc. ... (a total newbie here).



The obvious solution for me was quick and dirty: transform the Umlaut chars (present as HTML codes in my case) to their normal equivalent ('?' = 'ae', '?' = 'oe', 'ü' = 'ue', '?' = 'ss' etc.), sort the array, then transform back. However there are cases in which a 'Mueller' is really that and does NOT need to be transformed into 'Müller' afterwards. Hence I for example replace the Umlaut itself with it's normal equivalent plus a char not used in the string otherwise (e.g. '_') so that the transfer back to Umlaut would only take place on certain combinations.



Of course any other char instead of '_' can be used as additional char (influencing the sort result). I know that my solution is rough at the edges and may cause other sort problems but it was sufficient for my purpose.



The array '$dat' in this example was filled with German town names (I actually worked with a multiple array ('$dat[][]') but stripped the code down to this as it's easier to understand):



<?php

// START Pre-sorting (Umlaut -> normal letters)

$max = count($dat);

for($totcnt = 0; $totcnt < $max; $totcnt++){

   $dat[$totcnt]=str_replace('&szlig;','ss_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&Auml;','Ae_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&auml;','ae_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&Ouml;','Oe_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&ouml;','oe_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&Uuml;','Ue_',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('&uuml;','ue_',$dat[$totcnt]);

}

// END Pre-sorting (Umlaut -> normal letters)



// START Sorting //

function compare_towns($a, $b)

{

return strnatcmp($a, $b);

}

usort($dat, 'compare_towns');

// END Sorting //



// START Post-sorting (normal letters -> Umlaut)

for($totcnt = 0; $totcnt < $max; $totcnt++){

   $dat[$totcnt]=str_replace('ss_','&szlig;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('Ae_','&Auml;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('ae_','&auml;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('Oe_','&Ouml;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('oe_','&ouml;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('Ue_','&Uuml;',$dat[$totcnt]);

   $dat[$totcnt]=str_replace('ue_','&uuml;',$dat[$totcnt]);

}

// END Post-sorting (normal letters -> Umlaut)

?>

anaz114119 at gmail dot com 24-Dec-2010 02:34


sort from textfile by coloumn


example name||date||time||comments


if you want to sort by date


$column = 2


<?php


function array_sort($array,$column){


 $column = $column-1;


 foreach($array as $line){


 $bits = explode("||",$line);


 $bits ="$bits[$column]**$line";


 $array1[]=$bits;


}


 asort($array1);


 foreach($array1 as $line){


 $bit = explode("**",$line);


 $bit ="$bit[1]";


 $array2[]=$bit;


}


 return$array2;


}


?>

poulou_0 at hotmail dot com 21-Dec-2010 12:59


if you are not interested in high or low case sort



<?php

//where

$sortable_array[$k] = $v2; 

//put

$sortable_array[$k] = strtolower($v2);



//and where

$sortable_array[$k] = $v;

//put

$sortable_array[$k] = strtolower($v);

?>

phpdotnet at m4tt dot co dot uk 16-Aug-2010 07:03

eriewave at hotmail dot com 29-Mar-2010 01:16


If you need to sort an array containing some equivalent values and you want the equivalents to end up next to each other in the overall order (similar to a MySQL's ORDER BY output), rather than breaking the function, do this:



<?php



sort($array, ksort($array))



?>



-When the sort() function finds two equivalents, it will sort them arbitrarily by their key #'s as a second parameter.



-Dirk

Brecht Cloetens 23-Nov-2009 03:57


<?php

    

/**

 * function: array_columns

 * author: Brecht Cloetens

 * params: $a = array() // original array

 *         $c = int() // number of columns

 */

function array_columns(&$a, $c=2)

{

    $m = ceil(count($a)/$c);

    $j = 0;

    for($i=0; $i<$m; $i++) {

        for($k=0; $k<$c; $k++) {

            $key = $i+($m*$k);

            settype($key,'integer');

            if(array_key_exists($key,$a)) {

                $b[$j] = $a[$key];

                $j++;

            }

        }

    }

    $a = $b;

}



$arr = range('a','z');

array_columns($arr,4);

print_r($arr);



?>



Example:

array(1,2,3,4,5) will be converted to array(1,4,2,5,3);



This can be easy if you want to display an array into a specified number of columns.



<table>

    <tr>

        <td>$arr[0] => 1</td>

        <td>$arr[1] => 4</td>

    </tr>

    <tr>

        <td>$arr[2] => 2</td>

        <td>$arr[3] => 5</td>

    </tr>

    <tr>

        <td>$arr[4] => 3</td>

        <td></td>

    </tr>

</table>

petr dot biza at gmail dot com 11-Sep-2009 06:29


Here is a function to sort an array by the key of his sub-array with keep key in top level.





<?php


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


    $temp_array = $array;





    foreach ($temp_array as $key => &$value) {


      


      $sort = array();


      foreach ($value as $index => $val) {


          $sort[$index] = $val[$subkey];


      }


      


      asort($sort);


      


      $keys = array_keys($sort);


      $newValue = array();


      foreach ($keys as $index) {


        if($keep_keys_in_sub)


            $newValue[$index] = $value[$index];


          else


            $newValue[] = $value[$index];


      }


      


      if($sort_descending)


        $value = array_reverse($newValue, $keep_keys_in_sub);


      else


        $value = $newValue;


    }


    


    $array = $temp_array;


  }


?>

danm68 at gmail dot com 25-Aug-2009 09:59


sort() used with strings doesn't sort just alphabetically. It sorts all upper-case strings alphabetically first and then sorts lower-case strings alphabetically second. 

Just in case anyone was as confused as I was and I've never seen this mentioned anywhere.

stepmuel at ee dot ethz dot ch 09-Dec-2008 08:14


A little shorter way to sort an array of objects; with a callback function.



<?php 

function objSort(&$objArray,$indexFunction,$sort_flags=0) {

    $indices = array();

    foreach($objArray as $obj) {

        $indeces[] = $indexFunction($obj);

    }

    return array_multisort($indeces,$objArray,$sort_flags);

}



function getIndex($obj) {

    return $obj->getPosition();

}



objSort($objArray,'getIndex'); 

?>

www at designdetector dot com 09-Sep-2008 07:43


To sort an array of multiple text fields alphabetically you have to make the text lowercase before sorting the array. Otherwise PHP puts acronyms before words. You can see this in my example code. Simply store the original text field at the end of the array line and call it later from there. You can safely ignore the lowercase version which is added to the start of the array line.



<?php

echo '<pre>ORIGINAL DATA:

<br />';



$data = array(

'Saturn|7|8|9|0||',

'Hello|0|1|2|3||',

'SFX|5|3|2|4||',

'HP|9|0|5|6||'

);



print_r($data);



sort($data);

reset($data);



echo '<br />RAW SORT:

<br />';



print_r($data);



for ($c = 0; $c < count($data); $c++) {

    list ($letter,$g1,$g2,$g3,$g4,$end) = explode ('|', $data[$c]);

    $lowercase = strtolower($letter);

    $data2[$c] = array($lowercase,$g1,$g2,$g3,$g4,$letter);

}



sort($data2);

reset($data2);



echo '<br />LOWERCASE SORT:

<br />';



print_r($data2);



echo '</pre>';

?>

matpatnik at hotmail dot com 23-Jan-2008 03:46


This function will sort entity letters eg:&eacute;



I hope that help someone



function sort_entity($array) {

    $total = count($array);

    for ($i=0;$i<$total;$i++) {

        if ($array[$i]{0} == '&') {

            $array[$i] = $array[$i]{1}.$array[$i];

        } else {

            $array[$i] = $array[$i]{0}.$array[$i];

        }

    }

    sort($array);

    

    for ($i=0;$i<$total;$i++) {

        $array[$i] = substr($array[$i],1);

    }

    

    return $array;

}

sinan at sinaneldem dot com 23-Jun-2007 08:29


here is little script which will merge arrays, remove duplicates and sort it by alphabetical order:



<?php



$array1 = array('apple', 'banana','pear');

$array2 = array('grape', 'pear','orange');



function array_unique_merge_sort($array1, $array2){

$array = array_unique(array_merge($array1, $array2));

sort($array);

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

    $new[$key] = $value;

}

return $new;

}



print_r (array_unique_merge_sort($array1, $array2));



?>



this will print out:



Array ( [0] => apple [1] => banana [2] => grape [3] => orange [4] => pear )

alishahnovin at hotmail dot com 25-May-2007 04:11


I had a multidimensional array, which needed to be sorted by one of the keys. This is what I came up with...



<?php

function msort($array, $id="id") {

        $temp_array = array();

        while(count($array)>0) {

            $lowest_id = 0;

            $index=0;

            foreach ($array as $item) {

                if ($item[$id]<$array[$lowest_id][$id]) {

                    $lowest_id = $index;

                }

                $index++;

            }

            $temp_array[] = $array[$lowest_id];

            $array = array_merge(array_slice($array, 0,$lowest_id), array_slice($array, $lowest_id+1));

        }

        return $temp_array;

    }

?>



Ex:



<?php



//oh no, this is not in the ordered by id!!

$data[] = array("item"=>"item 4", "id"=>4);

$data[] = array("item"=>"item 1", "id"=>1);

$data[] = array("item"=>"item 3", "id"=>3);

$data[] = array("item"=>"item 2", "id"=>2);



var_dump(  msort($data)  ); //just msort it!



/* outputs 



array

  0 => 

    array

      'item' => 'item 1' (length=6)

      'id' => 1

  1 => 

    array

      'item' => 'item 2' (length=6)

      'id' => 2

  2 => 

    array

      'item' => 'item 3' (length=6)

      'id' => 3

  3 => 

    array

      'item' => 'item 4' (length=6)

      'id' => 4



*/



?>

joris at mangrove dot nl 01-Feb-2007 05:40


Commenting on note http://www.php.net/manual/en/function.sort.php#62311 :



Sorting an array of objects will not always yield the results you desire.



As pointed out correctly in the note above, sort() sorts the array by value of the first member variable. However, you can not always assume the order of your member variables! You must take into account your class hierarchy!



By default, PHP places the inherited member variables on top, meaning your first member variable is NOT the first variable in your class definition! 

However, if you use code analyzers or a compile cache, things can be very different. E.g., in eAccelerator, the inherited member variables are at the end, meaning you get different sort results with caching on or off.



Conclusion:

Never use sort on arrays with values of a type other than scalar or array.

alex [at] vkpb [dot] com 26-Jan-2007 03:36


Sorting of an array by a method of inserts.



<?



  

       function sortByField($multArray,$sortField,$desc=true){

            $tmpKey='';

            $ResArray=array();



            $maIndex=array_keys($multArray);

            $maSize=count($multArray)-1;



            for($i=0; $i < $maSize ; $i++) {



               $minElement=$i;

               $tempMin=$multArray[$maIndex[$i]][$sortField];

               $tmpKey=$maIndex[$i];



                for($j=$i+1; $j <= $maSize; $j++)

                  if($multArray[$maIndex[$j]][$sortField] < $tempMin ) {

                     $minElement=$j;

                     $tmpKey=$maIndex[$j];

                     $tempMin=$multArray[$maIndex[$j]][$sortField];



                  }

                  $maIndex[$minElement]=$maIndex[$i];

                  $maIndex[$i]=$tmpKey;

            }



           if($desc)

               for($j=0;$j<=$maSize;$j++)

                  $ResArray[$maIndex[$j]]=$multArray[$maIndex[$j]];

           else

              for($j=$maSize;$j>=0;$j--)

                  $ResArray[$maIndex[$j]]=$multArray[$maIndex[$j]];



           return $ResArray;

       }



// make array

$array['aaa']=array("name"=>"vasia","order"=>1);

$array['bbb']=array("name"=>"petia","order"=>2);

$array['ccc']=array("name"=>"kolia","order"=>3);

$array['ddd']=array("name"=>"zenia","order"=>4);



// set sort 

$SortOrder=0; // desc by default , 1- asc



var_dump(sortByField($array,'order',$SortOrder));



array

  'ddd' => 

    array

      'name' => 'zenia' (length=5)

      'order' => 4

  'aaa' => 

    array

      'name' => 'vasia' (length=5)

      'order' => 1

  'bbb' => 

    array

      'name' => 'petia' (length=5)

      'order' => 2

  'ccc' => 

    array

      'name' => 'kolia' (length=5)

      'order' => 3



?>

g8z at yahoo dot com 14-Jul-2006 04:28


<?php

/**

This sort function allows you to sort an associative array while "sticking" some fields.



$sticky_fields = an array of fields that should not be re-sorted. This is a method of achieving sub-sorts within contiguous groups of records that have common data in some fields.



For example:



$a = array();



$a []= array(

    'name'         => 'Sam',

    'age'         => 23,

    'hire_date'    => '2004-01-01'

);

$a []= array(

    'name'        => 'Sam',

    'age'        => 44,

    'hire_date'    => '2003-03-23'

);

$a []= array(

    'name'        => 'Jenny',

    'age'        => 20,

    'hire_date' => '2000-12-31'

);

$a []= array(

    'name'        => 'Samantha',

    'age'        => 50,

    'hire_date' => '2000-12-14'

);



$sticky_fields = array( 'name' );

print_r( stickysort( $a, 'age', DESC_NUM, $sticky_fields ) );



OUTPUT:



Array

(

    [0] => Array

        (

            [name] => Sam

            [age] => 44

            [hire_date] => 2003-03-23

        )

    [1] => Array

        (

            [name] => Sam

            [age] => 23

            [hire_date] => 2004-01-01

        )

    [2] => Array

        (

            [name] => Jenny

            [age] => 20

            [hire_date] => 2000-12-31

        )

    [3] => Array

        (

            [name] => Samantha

            [age] => 50

            [hire_date] => 2000-12-14

        )

)



Here's why this is the correct output - the "name" field is sticky, so it cannot change its sort order. Thus, the "age" field is only sorted as a sub-sort within records where "name" is identical. Thus, the "Sam" records are reversed, because 44 > 23, but Samantha remains at the bottom, even though her age is 50. This is a way of achieving "sub-sorts" and "sub-sub-sorts" (and so on) within records of identical data for specific fields.



Courtesy of the $5 Script Archive: http://www.tufat.com

**/



define( 'ASC_AZ', 1000 );

define( 'DESC_AZ', 1001 );

define( 'ASC_NUM', 1002 );

define( 'DESC_NUM', 1003 );



function stickysort( $arr, $field, $sort_type, $sticky_fields = array() ) {

    $i = 0;

    foreach ($arr as $value) {

        $is_contiguous = true;

        if(!empty($grouped_arr)) {

            $last_value = end($grouped_arr[$i]);



            if(!($sticky_fields == array())) {

                foreach ($sticky_fields as $sticky_field) {

                    if ($value[$sticky_field] <> $last_value[$sticky_field]) {

                        $is_contiguous = false;

                        break;

                    }

                }

            }

        }

        if ($is_contiguous)

            $grouped_arr[$i][] = $value;

        else

            $grouped_arr[++$i][] = $value;

    }

    $code = '';

    switch($sort_type) {

        case ASC_AZ:

            $code .= 'return strcasecmp($a["'.$field.'"], $b["'.$field.'"]);';

            break;

        case DESC_AZ:

            $code .= 'return (-1*strcasecmp($a["'.$field.'"], $b["'.$field.'"]));';

            break;

        case ASC_NUM:

            $code .= 'return ($a["'.$field.'"] - $b["'.$field.'"]);';

            break;

        case DESC_NUM:

            $code .= 'return ($b["'.$field.'"] - $a["'.$field.'"]);';

            break;

    }



    $compare = create_function('$a, $b', $code);



    foreach($grouped_arr as $grouped_arr_key=>$grouped_arr_value)

        usort ( $grouped_arr[$grouped_arr_key], $compare );



    $arr = array();

    foreach($grouped_arr as $grouped_arr_key=>$grouped_arr_value)

        foreach($grouped_arr[$grouped_arr_key] as $grouped_arr_arr_key=>$grouped_arr_arr_value)

            $arr[] = $grouped_arr[$grouped_arr_key][$grouped_arr_arr_key];



    return $arr;

}

?>

g8z at yahoo dot com 10-Jul-2006 08:58


<?php

/**

This sort function allows you to sort an associative array while "sticking" some fields.



$sticky_fields = an array of fields that should not be re-sorted. This is a method of achieving sub-sorts within contiguous groups of records that have common data in some fields.



Courtesy of the $5 Script Archive: http://www.tufat.com

**/



define( 'ASC_AZ', 1000 );

define( 'DESC_AZ', 1001 );

define( 'ASC_NUM', 1002 );

define( 'DESC_NUM', 1003 );



function stickysort( $arr, $field, $sort_type, $sticky_fields = array() ) {

    $i = 0;

    foreach ($arr as $value) {

        $is_contiguous = true;

        if(!empty($grouped_arr)) {

            $last_value = end($grouped_arr[$i]);



            if(!($sticky_fields == array())) {

                foreach ($sticky_fields as $sticky_field) {

                    if ($value[$sticky_field] <> $last_value[$sticky_field]) {

                        $is_contiguous = false;

                        break;

                    }

                }

            }

        }

        if ($is_contiguous)

            $grouped_arr[$i][] = $value;

        else

            $grouped_arr[++$i][] = $value;

    }

    $code = '';

    switch($sort_type) {

        case ASC_AZ:

            $code .= 'return strcasecmp($a["'.$field.'"], $b["'.$field.'"]);';

            break;

        case DESC_AZ:

            $code .= 'return (-1*strcasecmp($a["'.$field.'"], $b["'.$field.'"]));';

            break;

        case ASC_NUM:

            $code .= 'return ($a["'.$field.'"] - $b["'.$field.'"]);';

            break;

        case DESC_NUM:

            $code .= 'return ($b["'.$field.'"] - $a["'.$field.'"]);';

            break;

    }



    $compare = create_function('$a, $b', $code);



    foreach($grouped_arr as $grouped_arr_key=>$grouped_arr_value)

        usort ( $grouped_arr[$grouped_arr_key], $compare );



    $arr = array();

    foreach($grouped_arr as $grouped_arr_key=>$grouped_arr_value)

        foreach($grouped_arr[$grouped_arr_key] as $grouped_arr_arr_key=>$grouped_arr_arr_value)

            $arr[] = $grouped_arr[$grouped_arr_key][$grouped_arr_arr_key];



    return $arr;

}

?>

Emiliyan at ServicesBG dot Com 28-Mar-2006 07:41


#This is a function that will sort an array...

function sort_by($array,  $keyname = null, $sortby) {

   $myarray = $inarray = array();    

   # First store the keyvalues in a seperate array

    foreach ($array as $i => $befree) { 

        $myarray[$i] = $array[$i][$keyname];

    }

   # Sort the new array by

    switch ($sortby) {

    case 'asc':

    # Sort an array and maintain index association...

    asort($myarray); 

    break;

    case 'arsort':

    # Sort an array in reverse order and maintain index association 

    arsort($myarray); 

    break;

    case 'natcasesor':

    # Sort an array using a case insensitive "natural order" algorithm

    natcasesort($myarray); 

    break;

    }

    # Rebuild the old array

    foreach ( $myarray as $key=> $befree) {

       $inarray[$key] = $array[$key];

    }

    return $inarray;

} 

sort_by(); example...

$info = sort_by($myarray, 'name', $use = 'asc');    

print_r($info);

jesper at snt dot utwente dot nl 24-Feb-2006 01:26


If you sort an array of objects, the first variable in the object will be used for sorting:



<?php

class foo

{

  var $value; //First variable: Used for sorting

  var $id;



  function foo($i, $v)

  {

     $this->id = $i;

     $this->value = $v;

  }



}



for ($i = 0; $i < 10; $i++)

{

  $bar[] = new foo($i,rand(1,10));

}



// This will sort on value

sort($bar);

print_r($bar);

?>



Compare the piece of code above with the following:



<?php

class foo

{

  var $id; //First variable: Used for sorting

  var $value;



  function foo($i, $v)

  {

     $this->id = $i;

     $this->value = $v;

  }



}



for ($i = 0; $i = 10; $i++)

{

  $bar[] = new foo($i,rand(1,10));

}



// This will sort on id

sort($bar);

print_r($bar);

?>



As you can see the location of declaration of the variables matter!

If you want to sort on both or on a combination of variables, use ksort()

nm at thenoodleman dot com 30-Jan-2006 05:18


Faster, more effective function:



array_sort (array, ['asc'/'desc'])



Second parameter specifies whether to order ascending or descending. Default is ascending.



function array_sort($array, $type='asc'){

    $result=array();

    foreach($array as $var => $val){

        $set=false;

        foreach($result as $var2 => $val2){

            if($set==false){

                if($val>$val2 && $type=='desc' || $val<$val2 && $type=='asc'){

                    $temp=array();

                    foreach($result as $var3 => $val3){

                        if($var3==$var2) $set=true;

                        if($set){

                            $temp[$var3]=$val3;

                            unset($result[$var3]);

                        }

                    }

                    $result[$var]=$val;    

                    foreach($temp as $var3 => $val3){

                        $result[$var3]=$val3;

                    }

                }

            }

        }

        if(!$set){

            $result[$var]=$val;

        }

    }

    return $result;

}



Works for ordering by integers or strings, no need to specify which.



Example:



$array=array('a' => 50, 'b' => 25, 'c' => 75);

print_r(array_sort($array));



Returns:

Array

(

[b] => 25

[a] => 50

[c] => 75

)

raul at jimi dot com dot mx 01-Dec-2005 09:50


I had an array like this:

$arr=array (1,4,3,6,5);



which returns this:

$arr[0]=1

$arr[1]=4

$arr[2]=3

$arr[3]=6

$arr[4]=5



But lets say i remove [2] which is number 3, i get:



$arr[0]=1

$arr[1]=4

$arr[3]=6

$arr[4]=5



And i want to reindex without doing a sort because i dont want to lose the order of the numbers (like a pop in a stack but in the middle of the list), i do this:



$arr=array_chunk($arr,count($arr));

$arr=$arr[0];



the result is:



$arr[0]=1

$arr[1]=4

$arr[2]=6

$arr[3]=5



This can be applied mostly for tree sorting, when you only have the id and the parent values of the node, and you want to have N levels.

james at miicro dot net 19-Jul-2005 02:49


It's useful to know that if you're using this function on a multidimensional array, php will sort the first key, then the second and so on. This is similar to being able to use SQL to order by field1, field2 etc.



So:



Array ( 

[0] => Array ( [category] => work [name] => Smith ) 

[1] => Array ( [category] => play [name] => Johnson ) 

[2] => Array ( [category] => work [name] => Berger )

)



will become:



Array ( 

[0] => Array ( [category] => play [name] => Johnson )

[1] => Array ( [category] => work [name] => Berger ) 

[2] => Array ( [category] => work [name] => Smith ) 

)



Hope it helps someone.

timc at hlyw dot com 17-Feb-2005 04:04


I dig the multi_sort function(s) from above.  But, they don't work for hash arrays.  I added a keys variable to keep track of the key value as the array gets sorted.  Feed back welcome.



<?php

function array_qsort (&$array, $column=0, $order=SORT_ASC, $first=0, $last= -2) 

{ 

  // $array  - the array to be sorted 

  // $column - index (column) on which to sort 

  //          can be a string if using an associative array 

  // $order  - SORT_ASC (default) for ascending or SORT_DESC for descending 

  // $first  - start index (row) for partial array sort 

  // $last  - stop  index (row) for partial array sort 

  // $keys  - array of key values for hash array sort

  

  $keys = array_keys($array);

  if($last == -2) $last = count($array) - 1; 

  if($last > $first) { 

   $alpha = $first; 

   $omega = $last;

   $key_alpha = $keys[$alpha]; 

   $key_omega = $keys[$omega];

   $guess = $array[$key_alpha][$column]; 

   while($omega >= $alpha) { 

     if($order == SORT_ASC) { 

       while($array[$key_alpha][$column] < $guess) {$alpha++; $key_alpha = $keys[$alpha]; }

       while($array[$key_omega][$column] > $guess) {$omega--; $key_omega = $keys[$omega]; }

     } else { 

       while($array[$key_alpha][$column] > $guess) {$alpha++; $key_alpha = $keys[$alpha]; }

       while($array[$key_omega][$column] < $guess) {$omega--; $key_omega = $keys[$omega]; }

     } 

     if($alpha > $omega) break; 

     $temporary = $array[$key_alpha]; 

     $array[$key_alpha] = $array[$key_omega]; $alpha++;

     $key_alpha = $keys[$alpha];

     $array[$key_omega] = $temporary; $omega--;

     $key_omega = $keys[$omega];

   } 

   array_qsort ($array, $column, $order, $first, $omega); 

   array_qsort ($array, $column, $order, $alpha, $last); 

  } 

} 

?>

anthony at ectrolinux dot com 08-Sep-2004 04:39


In a brief addition to the previous poster's message, the ascending sorting order used by PHP directly corresponds to ISO-8859-1 (ASCII). Therefore the character \48 (numeral 0) would be placed before the character \82 (R), which would be placed before the character \110 (n), and so forth.

arjan321 at hotmail dot com 31-Jan-2003 12:23


Ik you want to sort case insensitive, use the natcasesort()

peek at mailandnews dot com 07-Apr-2001 04:06


I ran into the same problem with case insensitive sorting. Actually I think there should be a SORT_STRING_CASE flag but I tried the following:





usort($listing, 'strcasecmp');





This didn't work (why not?), but you can do a proper case insensitive sort like this:





usort($listing, create_function('$a,$b','return strcasecmp($a,$b);'));