uasort
(PHP 4, PHP 5)
uasort — Сортирует массив, используя пользовательскую функцию для сравнения элементов с сохранением ключей
Описание
Эта функция сортирует массив таким образом, что его индексы сохраняют отношения с элементами, с которыми ранее были ассоциированы, с помощью callback-функции, предоставленной пользователем.
Это обычно используется при сортировке ассоциативных массивов, в которых важен актуальный порядок элементов.
Список параметров
Возвращаемые значения
Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.
Примеры
Пример #1 Простой пример использования uasort()
<?php
// Функция сравнения
function cmp($a, $b) {
if ($a == $b) {
return 0;
}
return ($a < $b) ? -1 : 1;
}
// Сортируемый массив
$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);
print_r($array);
// Сортируем и выводим получившийся массив
uasort($array, 'cmp');
print_r($array);
?>
Результат выполнения данного примера:
Array
(
[a] => 4
[b] => 8
[c] => -1
[d] => -9
[e] => 2
[f] => 5
[g] => 3
[h] => -4
)
Array
(
[d] => -9
[h] => -4
[c] => -1
[e] => 2
[g] => 3
[a] => 4
[f] => 5
[b] => 8
)
Смотрите также
- usort() - Сортирует массив по значениям используя пользовательскую функцию для сравнения элементов
- Сравнение функций сортировки массивов
- PHP Руководство
- Индекс функций
- Справочник функций
- Расширения, относящиеся к переменным и типам
- Массивы
- array_change_key_case
- array_chunk
- array_combine
- array_count_values
- array_diff_assoc
- array_diff_key
- array_diff_uassoc
- array_diff_ukey
- array_diff
- array_fill_keys
- array_fill
- array_filter
- array_flip
- array_intersect_assoc
- array_intersect_key
- array_intersect_uassoc
- array_intersect_ukey
- array_intersect
- array_key_exists
- array_keys
- array_map
- array_merge_recursive
- array_merge
- array_multisort
- array_pad
- array_pop
- array_product
- array_push
- array_rand
- array_reduce
- array_replace_recursive
- array_replace
- array_reverse
- array_search
- array_shift
- array_slice
- array_splice
- array_sum
- array_udiff_assoc
- array_udiff_uassoc
- array_udiff
- array_uintersect_assoc
- array_uintersect_uassoc
- array_uintersect
- array_unique
- array_unshift
- array_values
- array_walk_recursive
- array_walk
- array
- arsort
- asort
- compact
- count
- current
- each
- end
- extract
- in_array
- key
- krsort
- ksort
- list
- natcasesort
- natsort
- next
- pos
- prev
- range
- reset
- rsort
- shuffle
- sizeof
- sort
- uasort
- uksort
- usort
Коментарии
Use example:
$array[0]['Fator1']=7;
$array[0]['Fator2']="Name";
$array[1]['Fator1']=5;
$array[1]['Fator2']="Name";
$array[2]['Fator1']=7;
$array[2]['Fator2']="NameDiferente";
.....
We want to order by Fator1, then Fator2, then:
function Compare($ar1, $ar2)
{
if ($ar1['Fator1']<$ar2['Fator1'])
return -1;
else if ($ar1['Fator1']>$ar2['Fator1'])
return 1;
if ($ar1['Fator2']<$ar2['Fator2'])
return -1;
else if ($ar1['Fator2']>$ar2['Fator2'])
return 1;
return 0;
}
To sort now, we use:
uasort($array, 'Compare');
Here is a little sort function that actually uses a dynamic callback for usort to do it's thing.
It assumes your data is in the form of:
$data = array(
array('ID'=>'6','LAST'=>'Holmes','FIRST'=>'Dan'),
array('ID'=>'1234','LAST'=>'Smith','FIRST'=>'Agent K'),
array('ID'=>'2','LAST'=>'Smith','FIRST'=>'Agent J'),
array('ID'=>'4','LAST'=>'Barney','FIRST'=>'Bob'));
Now, you want to sort on one or more cols, don't you?
masort($data, 'LAST,FIRST');
or
masort($data,array('FIRST','ID'));
Of course you could add a bunch to it (like numeric comparison if appropriate, desc/asc, etc) but it works for me.
function masort(&$data, $sortby){
if(is_array($sortby)){
$sortby = join(',',$sortby);
}
uasort($data,create_function('$a,$b','$skeys = split(\',\',\''.$sortby.'\');
foreach($skeys as $key){
if( ($c = strcasecmp($a[$key],$b[$key])) != 0 ){
return($c);
}
}
return($c); '));
}
Notice that I am splitting the string in the comparison function? While this is certainly slower, it was the only way I would find to "pass" and "array". If anyone has a better way, please suggest. Then inside, we (string) compare the values only moving to the next key if the values are the same...and so on, and so on.
You can sort a multidimensionnal array by any of its key with this function:
function multi_sort($array, $key)
{
$cmp_val="((\$a['$key']>\$b['$key'])?1:
((\$a['$key']==\$b['$key'])?0:-1))";
$cmp=create_function('$a, $b', "return $body;");
uasort($array, $cmp);
return $array;
}
example:
$myarray = array(
array("name"=>"kernighan", "language"=>"c"),
array("name"=>"lerdorf", "language"=>"php"),
array("name"=>"Stroustrup", "language"=>"c++"),
array("name"=>"Gosling", "language"=>"java")
);
multi_sort($myarray, "name") returns:
name=Gosling language=java
name=Kernighan language=c
name=Lerdorf language=php
name=Stroustrup language=c++
Is it just me, or are the examples below misleading, and actually demonstrating situations that would be more appropriate for usort()?
After trying to make sense of the uasort() description, it sounds like it's more for sorting a 1D array like this:
"john" => "$23.12"
"tim" => "$6.50"
"bob" => "$18.54"
and getting back:
"tim" => "$6.50"
"bob" => "$18.54"
"john" => $23.12"
(assuming, of course, that your sort function is lopping off the $ and evaluating as a number -- which would complicate the use of asort() ;)
dholmes we turned your masort function into a smarty plugin:
http://www.phpinsider.com/smarty-forum/viewtopic.php?t=1079
messju contributed the following performance improvements.
function masort(&$data, $sortby)
{
static $sort_funcs = array();
if (empty($sort_funcs[$sortby])) {
$code = "\$c=0;";
foreach (split(',', $sortby) as $key) {
$code .= "if ( (\$c = strcasecmp(\$a['$key'],\$b['$key'])) != 0 ) return \$c;\n";
}
$code .= 'return $c;';
$sort_func = $sort_funcs[$sortby] = create_function('$a, $b', $code);
} else {
$sort_func = $sort_funcs[$sortby];
}
$sort_func = $sort_funcs[$sortby];
uasort($data, $sort_func);
}
thank you for the cool function!
Hope this helps!
- Remmy
<?php
// Based on the other notes given before.
// Sorts an array (you know the kind) by key
// and by the comparison operator you prefer.
// Note that instead of most important criteron first, it's
// least important criterion first.
// The default sort order is ascending, and the default sort
// type is strnatcmp.
// function multisort($array[, $key, $order, $type]...)
function multisort($array)
{
for($i = 1; $i < func_num_args(); $i += 3)
{
$key = func_get_arg($i);
$order = true;
if($i + 1 < func_num_args())
$order = func_get_arg($i + 1);
$type = 0;
if($i + 2 < func_num_args())
$type = func_get_arg($i + 2);
switch($type)
{
case 1: // Case insensitive natural.
$t = 'strcasenatcmp($a[' . $key . '], $b[' . $key . '])';
break;
case 2: // Numeric.
$t = '$a[' . $key . '] - $b[' . $key . ']';
break;
case 3: // Case sensitive string.
$t = 'strcmp($a[' . $key . '], $b[' . $key . '])';
break;
case 4: // Case insensitive string.
$t = 'strcasecmp($a[' . $key . '], $b[' . $key . '])';
break;
default: // Case sensitive natural.
$t = 'strnatcmp($a[' . $key . '], $b[' . $key . '])';
break;
}
uasort($array, create_function('$a, $b', 'return ' . ($order ? '' : '-') . '(' . $t . ');'));
}
return $array;
}
$a = array(
array('id' => 1, 'name' => 'apple'),
array('id' => 2, 'name' => 'orange'),
array('id' => 8, 'name' => 'banana'),
array('id' => 8, 'name' => 'grapefruit'),
array('id' => 9, 'name' => 'smoke'),
array('id' => 1, 'name' => 'screen')
);
// This works like MYSQL 'ORDER BY id DESC, name ASC'
// Note the quoting of string literal keys.
echo('<pre>');
print_r(multisort($a, "'name'", true, 0, "'id'", false, 2));
echo('</pre>');
?>
regarding remmy.cjb.net (22-Oct-2003 05:57) note:
The "multisort" function is not working. Try the following example.
( I hope this and your note will be deleted soon.)
..- Denis
<?php
$a = array(
array('c1' => 1, 'c2' => 1, 'c3' => 1, 'c4' => 1),
array('c1' => 1, 'c2' => 1, 'c3' => 1, 'c4' => 2),
array('c1' => 1, 'c2' => 1, 'c3' => 2, 'c4' => 1),
array('c1' => 1, 'c2' => 1, 'c3' => 2, 'c4' => 2)
);
echo('<pre>');
print_r(multisort($a, "'c4'", true, 2,"'c3'", true, 2,"'c2'", true, 2,"'c1'", true, 2));
echo('</pre>');
?>
WARNING:-Regarding remmy.cjb.net (22-Oct-2003 05:57) mutisort() function:
Sorting by floating point numbers doesn't work in the current function. Use the modified version below if you want to sort by a floating point column.
<?php
// Based on the other notes given before.
// Sorts an array (you know the kind) by key
// and by the comparison operator you prefer.
// Note that instead of most important criteron first, it's
// least important criterion first.
// The default sort order is ascending, and the default sort
// type is strnatcmp.
// function multisort($array[, $key, $order, $type]...)
function multisort($array)
{
for($i = 1; $i < func_num_args(); $i += 3)
{
$key = func_get_arg($i);
if (is_string($key)) $key = '"'.$key.'"';
$order = true;
if($i + 1 < func_num_args())
$order = func_get_arg($i + 1);
$type = 0;
if($i + 2 < func_num_args())
$type = func_get_arg($i + 2);
switch($type)
{
case 1: // Case insensitive natural.
$t = 'strcasecmp($a[' . $key . '], $b[' . $key . '])';
break;
case 2: // Numeric.
$t = '($a[' . $key . '] == $b[' . $key . ']) ? 0:(($a[' . $key . '] < $b[' . $key . ']) ? -1 : 1)';
break;
case 3: // Case sensitive string.
$t = 'strcmp($a[' . $key . '], $b[' . $key . '])';
break;
case 4: // Case insensitive string.
$t = 'strcasecmp($a[' . $key . '], $b[' . $key . '])';
break;
default: // Case sensitive natural.
$t = 'strnatcmp($a[' . $key . '], $b[' . $key . '])';
break;
}
echo $t;
usort($array, create_function('$a, $b', '; return ' . ($order ? '' : '-') . '(' . $t . ');'));
}
return $array;
}
?>
Below another array sorting function - you can use many keys, whether order type is ascendant or descendant, if values of given key should be treat as string or numeric, if array keys should be preserved. This function is locale-safe - it means that string sorting will be based on setLocale settings. You should be aware that I did not make comprehensive tests, so be careful...
// my locales
SetLocale(LC_COLLATE,"pl_PL.UTF-8");
SetLocale(LC_CTYPE, "pl_PL.UTF-8");
function Array_Sort ($array, $arguments = Array(), $keys = true) {
// comparing function code
$code = "";
// foreach sorting argument (array key)
foreach ($arguments as $argument) {
// order field
$field = substr($argument, 2, strlen($argument));
// sort type ("s" -> string, "n" -> numeric)
$type = $argument[0];
// sort order ("+" -> "ASC", "-" -> "DESC")
$order = $argument[1];
// add "if" statement, which checks if this argument
should be used
$code .= "if (!Is_Numeric(\$result) || \$result == 0) ";
// if "numeric" sort type
if (strtolower($type) == "n") $code .= $order == "-" ? "\$result = (\$a['{$field}'] > \$b['{$field}'] ? -1 : (\$a['{$field}'] < \$b['{$field}'] ? 1 : 0));" : "\$result = (\$a['{$field}'] > \$b['{$field}'] ? 1 : (\$a['{$field}'] < \$b['{$field}'] ? -1 : 0));";
// if "string" sort type
else $code .= $order == "-" ? "\$result = strcoll(\$a['{$field}'], \$b['{$field}']) * -1;" : "\$result = strcoll(\$a['{$field}'], \$b['{$field}']);";
}
// return result
$code .= "return \$result;";
// create comparing function
$compare = create_function('$a, $b', $code);
// sort array and preserve keys
if ($keys) uasort($array, $compare);
// sort array, but not preserve keys
else usort($array, $compare);
// return array
return $array;
}
Example array:
$array['sdsd'] = array("dir" => 1, "name" => "sas", "olek" => "sdsd");
$array['sds2'] = array("dir" => 2, "name" => "śas", "olek" => "t");
Example - preserve keys:
print_r(Array_Sort($array, Array("s-name", "n-dir", "s+olek")));
Array
(
[sds2] => Array
(
[dir] => 1
[name] => śas
[olek] => t
)
[sdsd] => Array
(
[dir] => 1
[name] => sas
[olek] => sdsd
)
)
Example - without preserving keys:
print_r(Array_Sort($array, Array("s-name", "n-dir", "s+olek")), false);
Array
(
[0] => Array
(
[dir] => 1
[name] => śas
[olek] => t
)
[1] => Array
(
[dir] => 1
[name] => sas
[olek] => sdsd
)
)
Enyoj
Hello naholyr at yahoo dot fr!
should it be
$cmp = create_function('$a, $b', "return $cmp_val;");
?
this works with my arrays ;-)
regards, Christopher
The following is a modification of the dholme/messju masort func using david's float code with automatic data type detection. As long as the value isn't a string numeral (I.E. "1", '13.4') this should sort strings and numbers without having to explicity set which they are.
<?php
function masort(&$data, $sortby)
{
static $sort_funcs = array();
if (empty($sort_funcs[$sortby])) {
$code = "\$c=0;";
foreach (split(',', $sortby) as $key) {
$array = array_pop($data);
array_push($data, $array);
if(is_numeric($array[$key]))
$code .= "if ( \$c = ((\$a['$key'] == \$b['$key']) ? 0:((\$a['$key'] < \$b['$key']) ? -1 : 1 )) );";
else
$code .= "if ( (\$c = strcasecmp(\$a['$key'],\$b['$key'])) != 0 ) return \$c;\n";
}
$code .= 'return $c;';
$sort_func = $sort_funcs[$sortby] = create_function('$a, $b', $code);
} else {
$sort_func = $sort_funcs[$sortby];
}
$sort_func = $sort_funcs[$sortby];
uasort($data, $sort_func);
}
?>
A subtle bug, corrected...
<?php
function masort(&$data, $sortby)
{
static $sort_funcs = array();
if (empty($sort_funcs[$sortby])) {
$code = "\$c=0;";
foreach (split(',', $sortby) as $key) {
$array = array_pop($data);
array_push($data, $array);
if(is_numeric($array[$key]))
$code .= "if ( \$c = ((\$a['$key'] == \$b['$key']) ? 0:((\$a['$key'] < \$b['$key']) ? -1 : 1 )) ) return \$c;";
else
$code .= "if ( (\$c = strcasecmp(\$a['$key'],\$b['$key'])) != 0 ) return \$c;\n";
}
$code .= 'return $c;';
$sort_func = $sort_funcs[$sortby] = create_function('$a, $b', $code);
} else {
$sort_func = $sort_funcs[$sortby];
}
$sort_func = $sort_funcs[$sortby];
uasort($data, $sort_func);
}
?>
Note that
$code .= "if ( \$c = ((\$a['$key'] == \$b['$key']) ? 0:((\$a['$key'] < \$b['$key']) ? -1 : 1 )) ) return \$c;";
Has had the "return \$c" added. Ultimately what the method is trying to accomplish is to build a chain of sort-order precedence. But this requires each evaluation to short-circuit out with a return. It was missing.
Peace
Using uasort to alphabetically sort nested objects:
In this example, a "collection" object contains an array of "dataItem" objects which consist of a string name, a string attribute x and an arbitrary integer y.
This code allows you to sort the dataset by any of the dataItem attributes, or the order in which they were originally added to the set.
I'm using PHP 4.23 at work at the moment for legacy reasons, so I wrote the example following that object model.
<?php
class dataItem
{
var $name;
var $x;
//Constructor
function dataItem($name,$x,$y)
{
$this->name = $name;
$this->x = $x;
$this->y = $y;
}
}
class collection
{
var $dataSet = array();
//Creates a new data item and adds it to our array
function add($name,$x,$y)
{
$this->dataSet[] = new dataItem($name,$x,$y);
}
//The wrapper sort function
function sortDataSet($s)
{
//Sort by the given parameter
switch($s)
{
case "name":
//Note use of array to reference member method of this object in callback
uasort($this->dataSet,array($this,"cmpName"));
break;
case "x":
uasort($this->dataSet,array($this,"cmpX"));
break;
case "y":
uasort($this->dataSet,array($this,"cmpY"));
break;
case "added":
default:
//Re-sort array by original keys
ksort($this->dataSet);
}
}
//Callback function for sorting by name
//$a and $b are dataItem objects
function cmpName($a,$b)
{
//Use sort() for simple alphabetical comparison
//Convert to lowercase to ensure consistent behaviour
$sortable = array(strtolower($a->name),strtolower($b->name));
$sorted = $sortable;
sort($sorted);
//If the names have switched position, return -1. Otherwise, return 1.
return ($sorted[0] == $sortable[0]) ? -1 : 1;
}
//Callback function for sorting by x
//$a and $b are dataItem objects
function cmpX($a,$b)
{
//Use sort() for simple alphabetical comparison
//Convert to lowercase to ensure consistent behaviour
$sortable = array(strtolower($a->x),strtolower($b->x));
$sorted = $sortable;
sort($sorted);
//If the names have switched position, return -1. Otherwise, return 1.
return ($sorted[0] == $sortable[0]) ? -1 : 1;
}
//Callback function for sorting by y
//$a and $b are dataItem objects
function cmpY($a,$b)
{
//If $a's y attribute >= $b's y attribute, return 1. Otherwise, return -1.
return ($a->y >= $b->y) ? 1 : -1;
}
}
//Create a collection object
$myCollection = new collection();
//Add a few "records"
$myCollection->add("pancake","egg",7);
$myCollection->add("France","Paris",2);
$myCollection->add("Naked Gun","Leslie Nielsen",1);
$myCollection->add("OSX","huge icons",33);
$myCollection->add("telephone","keypad",-3);
//Test the output
//Sort by name:
$myCollection->sortDataSet("name");
print_r($myCollection->dataSet);
//Sort by x
$myCollection->sortDataSet("x");
print_r($myCollection->dataSet);
//Sort by y
$myCollection->sortDataSet("y");
print_r($myCollection->dataSet);
//Sort by order added
$myCollection->sortDataSet("added");
print_r($myCollection->dataSet);
?>
Will give this output (Anotated and re-formatted for ease of reading):
Sorted by name:
France Paris 2
Naked Gun Leslie Nielsen 1
OSX huge icons 33
pancake egg 7
telephone keypad -3
Sorted by x:
pancake egg 7
OSX huge icons 33
telephone keypad -3
Naked Gun Leslie Nielsen 1
France Paris 2
Sorted by y:
telephone keypad -3
Naked Gun Leslie Nielsen 1
France Paris 2
pancake egg 7
OSX huge icons 33
Sorted as added:
pancake egg 7
France Paris 2
Naked Gun Leslie Nielsen 1
OSX huge icons 33
telephone keypad -3
This is obviously a trivial case, but it can be very useful for larger data structures.
Difference between uasort() and usort(), the missing example ...
<?php
$arr = array ( 10 => array('id' => 'dix', 'aa' => '1010'),
100 => array('id' => 'cent', 'aa' => '100100'),
2 => array('id' => 'deux', 'aa' => '22'),
7 => array('id' => 'sept', 'aa' => '77'));
// id sorting
function so ($a, $b) { return (strcmp ($a['id'],$b['id'])); }
?>
*** uasort($arr, 'so') output:
<?php Array (
[100] => Array
(
[id] => cent
[aa] => 100100
)
[2] => Array
(
[id] => deux
[aa] => 22
)
[10] => Array
(
[id] => dix
[aa] => 1010
)
[7] => Array
(
[id] => sept
[aa] => 77
))?>
*** usort($arr, 'so') output:
<?php Array (
[0] => Array
(
[id] => cent
[aa] => 100100
)
[1] => Array
(
[id] => deux
[aa] => 22
)
[2] => Array
(
[id] => dix
[aa] => 1010
)
[3] => Array
(
[id] => sept
[aa] => 77
))?>
I couldn't work out a way to specify what element to sort by using the existing php functions - maybe I didn't look hard enough?? So i wrote my own multidimensional array sorting class.
<?php
$stock = array(array("id" => 1,"item" => "hat",
"number" => 5, "price" => 15),
array("id" => 5,"item" => "shoes",
"number" => 1, "price" => 50),
array("id" => 3,"item" => "tie",
"number" => 2, "price" => 30));
$sort = new multiSort();
//will sort the array by id in ascending order
print_r ($sort->sortArray($stock,'id','rcmp'));
//will sort the array by id in descending order
print_r ($sort->sortArray($stock,'id','cmp'));
//can also be used like so (specifying the index of the array)
print_r ($sort->sortArray($stock,'0','rcmp'));
//////////////////////////////////////////////////////
class multiSort {
function sortArray($array,$parameter,$_function) { return $this->_uasort($array,$_function,$parameter); }
function cmp ($a, $b, $p) { return (strcmp ($a[$p],$b[$p]));}
function rcmp ($a, $b, $p) { return -1 * (strcmp ($a[$p],$b[$p]));}
function _uasort($array,$func,$param) {
for($i=0;$i<sizeof($array);$i++) {
$tmp = $i;
for($j=1;$j<sizeof($array);$j++) {
$result = $this->$func($array[$tmp],$array[$j],$param);
if($result == -1) {
$array = $this->arraySwap($array,$tmp,$j);
$tmp = $j;
}
}
}
return $array;
}
function arrayswap($arr, $src, $dst) {
$tmp = $arr[$dst];
$arr[$dst] = $arr[$src];
$arr[$src] = $tmp;
return $arr;
}
}
//////////////////////////////////////////////////////////
?>
hope someone finds this useful.
Just expanding on php arobase kochira period com's method:
If you are looking to sort a multi-D array by a specific column and have entries in both upper and lower case, simply drop the entries to lowercase before doing the strcmp.
<?php
$dirs = array(
array('name' => 'First Folder', 'path' => 'sompath'),
array('name' => 'second folder', 'path' => 'sompath2'),
array('name' => 'Third Folder', 'path' => 'sompath3')
);
function so($a, $b) {
return (strcmp (strtolower($a['name']), strtolower($b['name'])));
}
?>
To sort string containing Umlauts you can use this callback function:
<?php
function sortWUmlauts($s1, $s2)
{
$search = array('Ä','Ö','Ü','ß');
$replace = array('A','O','U','s');
return strcmp(
str_ireplace($search, $replace, $s1),
str_ireplace($search, $replace, $s2)
);
}
?>
simply call:
<?php uasort($array, 'sortWUmlauts'); ?>
I tried using some of the previous built multisorts, but they weren't working as expected.
So, I made my own Class, and it seems to work wonderfully.
Here is the code:
<?php
/************************************
* Allows sorting multi-dimensional
* arrays by a specific key and in
* asc or desc order
**/
class multiSort
{
var $key; //key in your array
//runs the sort, and returns sorted array
function run ($myarray, $key_to_sort, $type_of_sort = '')
{
$this->key = $key_to_sort;
if ($type_of_sort == 'desc')
uasort($myarray, array($this, 'myreverse_compare'));
else
uasort($myarray, array($this, 'mycompare'));
return $myarray;
}
//for ascending order
function mycompare($x, $y)
{
if ( $x[$this->key] == $y[$this->key] )
return 0;
else if ( $x[$this->key] < $y[$this->key] )
return -1;
else
return 1;
}
//for descending order
function myreverse_compare($x, $y)
{
if ( $x[$this->key] == $y[$this->key] )
return 0;
else if ( $x[$this->key] > $y[$this->key] )
return -1;
else
return 1;
}
}
?>
Took me some time to figure that out:
the user function must return an *integer*, if you return a float, you may not get the expected result.
<?php
$a = ('a' => 0.9, 'b' => 0.7, 'c' => 0.8);
function sorting($a, $b) { return $a - $b; }
// The function above will not =work, you have to
function sorting($a, $b)
{
$d = $a = $b;
return $d < 0 ? -1 : ($d > 0 ? 1 : 0);
}
?>
a quick reminder on the syntax if you want to use uasort in a Class or Object:
<?php
// procedural:
uasort($collection, 'my_sort_function');
// Object Oriented
uasort($collection, array($this, 'mySortMethod'));
// Objet Oriented with static method
uasort($collection, array('self', 'myStaticSortMethod'));
?>
An Example using anonymous function.Anonymous functions make some time the code easier to understand.
<?php
$fruits = array('Orange9','Orange11','Orange10','Orange6','Orange15');
uasort ( $fruits , function ($a, $b) {
return strnatcmp($a,$b); // or other function/code
}
);
print_r($fruits);
?>
returns
Array
(
[3] => Orange6
[0] => Orange9
[2] => Orange10
[1] => Orange11
[4] => Orange15
)
In case you need to sort an associative array by one of its keys, this function might be useful:
<?php
function sortByOneKey(array $array, $key, $asc = true) {
$result = array();
$values = array();
foreach ($array as $id => $value) {
$values[$id] = isset($value[$key]) ? $value[$key] : '';
}
if ($asc) {
asort($values);
}
else {
arsort($values);
}
foreach ($values as $key => $value) {
$result[$key] = $array[$key];
}
return $result;
}
?>
Consider the following example:
<?php
$users = array(
1 => array('name' => 'John', 'age' => 35),
2 => array('name' => 'Alice', 'age' => 23),
3 => array('name' => 'Bob', 'age' => 26)
);
$sortedByNameAsc = sortByOneKey($users, 'name');
$sortedByNameDesc = sortByOneKey($users, 'name', false);
echo "Sorted by Name in ascending order: ";
echo "<pre>" . print_r($sortedByNameAsc, true) . "</pre>";
echo "<br /><br />Sorted by Name in descending order: ";
echo "<pre>" . print_r($sortedByNameDesc, true) . "</pre>";
?>
The output will be the following:
Sorted by Name in ascending order:
Array
(
[2] => Array
(
[name] => Alice
[age] => 23
)
[3] => Array
(
[name] => Bob
[age] => 26
)
[1] => Array
(
[name] => John
[age] => 35
)
)
Sorted by Name in descending order:
Array
(
[1] => Array
(
[name] => John
[age] => 35
)
[3] => Array
(
[name] => Bob
[age] => 26
)
[2] => Array
(
[name] => Alice
[age] => 23
)
)
for a simple case insensitive compare you can use this (php >= 5.3):
<?php
$greetings = array('howdy', 'Hey', 'aloha he');
uasort($a, function($a, $b){ return strcasecmp($a, $b); });
//$a == array('aloha he', 'howdy', 'Hey');
?>
My simple and effective solution for sort multi-dimensional array by any key:
<?php
function sort_by_key ($arr,$key) {
global $key2sort;
$key2sort = $key;
uasort($arr, 'sbk');
return ($arr);
}
function sbk ($a, $b) {global $key2sort; return (strcasecmp ($a[$key2sort],$b[$key2sort]));}
?>