sort
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
))?>
uasort
(PHP 4, PHP 5)
uasort — Sort an array with a user-defined comparison function and maintain index association
Description
This function sorts an array such that array indices maintain their correlation with the array elements they are associated with, using a user-defined comparison function.
This is used mainly when sorting associative arrays where the actual element order is significant.
Parameters
Return Values
Returns TRUE on success or FALSE on failure.
add a note
User Contributed Notesuasort
php arobase kochira period com
08-Jun-2008 01:13
08-Jun-2008 01:13
joeseed86 at gmail dot com
04-Jan-2007 06:54
04-Jan-2007 06:54
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.
rlynch at lynchmarks dot com
17-May-2005 02:36
17-May-2005 02:36
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['$key']) ? -1 : 1 )) ) return \$c;";
Has had the "return \$c" added. Ultimately what the method is trying to accomplish is to build a chain of sort-order precedence. But this requires each evaluation to short-circuit out with a return. It was missing.
Peace
lucas dot karisny at linuxmail dot org
13-Feb-2005 03:09
13-Feb-2005 03:09
The following is a modification of the dholme/messju masort func using david's float code with automatic data type detection. As long as the value isn't a string numeral (I.E. "1", '13.4') this should sort strings and numbers without having to explicity set which they are.
<?php
function masort(&$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);
}
?>
siefer at sym dot net
04-Oct-2004 11:24
04-Oct-2004 11:24
Hello naholyr at yahoo dot fr!
should it be
$cmp = create_function('$a, $b', "return $cmp_val;");
?
this works with my arrays ;-)
regards, Christopher
marek at lewczuk dot com
27-May-2004 01:01
27-May-2004 01:01
Below another array sorting function - you can use many keys, whether order type is ascendant or descendant, if values of given key should be treat as string or numeric, if array keys should be preserved. This function is locale-safe - it means that string sorting will be based on setLocale settings. You should be aware that I did not make comprehensive tests, so be careful...
// my locales
SetLocale(LC_COLLATE,"pl_PL.UTF-8");
SetLocale(LC_CTYPE, "pl_PL.UTF-8");
function Array_Sort ($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($array, Array("s-name", "n-dir", "s+olek")), false);
Array
(
[0] => Array
(
[dir] => 1
[name] => śas
[olek] => t
)
[1] => Array
(
[dir] => 1
[name] => sas
[olek] => sdsd
)
)
Enyoj
david [__at__] castlelaing.com
10-May-2004 06:28
10-May-2004 06:28
WARNING:-Regarding remmy.cjb.net (22-Oct-2003 05:57) mutisort() function:
Sorting by floating point numbers doesn't work in the current function. Use the modified version below if you want to sort by a floating point column.
<?php
// Based on the other notes given before.
// Sorts an array (you know the kind) by key
// and by the comparison operator you prefer.
// Note that instead of most important criteron first, it's
// least important criterion first.
// The default sort order is ascending, and the default sort
// type is strnatcmp.
// function multisort($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;
}
?>
dn dot php at gmx dot de
24-Nov-2003 01:34
24-Nov-2003 01:34
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>');
?>
remmy.cjb.net
22-Oct-2003 08:57
22-Oct-2003 08:57
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>');
?>
cablehead
16-Sep-2003 06:08
16-Sep-2003 06:08
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!
php at eden2 dot com
17-Jul-2003 01:36
17-Jul-2003 01:36
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() ;)
naholyr at yahoo dot fr
10-Jan-2003 06:35
10-Jan-2003 06:35
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++
dholmes at jccc d0t net
09-Oct-2002 11:27
09-Oct-2002 11:27
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.
stilgar_cpsNOSPAM at zipmail dot NOSPAMcom dot br
05-Sep-2001 11:30
05-Sep-2001 11:30
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');