PHP Doku:: Entfernt doppelte Werte aus einem Array - function.array-unique.html

Verlauf / Chronik / History: (1) anzeigen

Sie sind hier:
Doku-StartseitePHP-HandbuchFunktionsreferenzVariablen- und typbezogene ErweiterungenArraysArray Funktionenarray_unique

Ein Service von Reinhard Neidl - Webprogrammierung.

Array Funktionen

<<array_uintersect

array_unshift>>

array_unique

(PHP 4 >= 4.0.1, PHP 5)

array_uniqueEntfernt doppelte Werte aus einem Array

Beschreibung

array array_unique ( array $array [, int $sort_flags = SORT_STRING ] )

Erwartet ein array und gibt ein neues Array zurück, aus dem alle doppelten Einträge entfernt wurden.

Beachten Sie, dass Schlüssel bewahrt bleiben. Erst behandelt array_unique() die Werte als Strings und sortiert sie, danach wird der erste gefundene Schlüssel behalten, und alle folgenden Schlüssel ignoriert. Das heißt nicht, dass der Schlüssel des ersten zugehörigen Wertes aus dem unsortierten array behalten wird.

Hinweis: Zwei Elemente werden nur dann als gleich angesehen, wenn (string) $elem1 === (string) $elem2. In Worten: Wenn die String-Repräsentation die gleiche ist. Das erste Element wird verwendet.

Parameter-Liste

array

Das Eingabe-Array.

sort_flags

Der optionale zweite Parameter sort_flags kann mit den folgenden Werten genutzt werden, um das Sortierverhalten zu ändern:

Sorting type flags:

  • SORT_REGULAR - vergleicht die Einträge normal (keine Typänderung)
  • SORT_NUMERIC - vergleicht die Einträge numerisch
  • SORT_STRING - vergleicht die Einträge als Strings
  • SORT_LOCALE_STRING - vergleicht die Einträge als Strings, basierend auf der aktuellen Locale. i18n_loc_set_default()-Funktion benutzen.

Rückgabewerte

Gibt das gefilterte Array zurück.

Changelog

Version Beschreibung
5.2.10 Der Standardwert von sort_flags wurde auf SORT_STRING zurückgesetzt.
5.2.9 Der optionale Parameter sort_flags wurde mit dem Standardwert SORT_REGULA hinzugefügt. Vor 5.2.9 wurde die Sortierung intern mit SORT_STRING durchgeführt.

Beispiele

Beispiel #1 array_unique()-Beispiel

<?php
$input 
= array("a" => "grün""rot""b" => "grün""blau""rot");
$result array_unique($input);
print_r($result);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Array
(
    [a] => grün
    [0] => rot
    [1] => blau
)

Beispiel #2 array_unique() und Typen

<?php
$input 
= array(4"4""3"43"3");
$result array_unique($input);
var_dump($result);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

array(2) {
  [0] => int(4)
  [2] => string(1) "3"
}

Anmerkungen

Hinweis: Beachten Sie, dass array_unique() nicht dazu gedacht ist, auf mehrdimensionalen Arrays zu arbeiten.


77 BenutzerBeiträge:
- Beiträge aktualisieren...
simon
11.10.2010 14:01
if you want to close the gaps into the keys after using array_unique() you can use array_values() afterwards. Example:

<?php
a
= array("one", "two", "two", "three")
a = array_unique(a);
/* will lead to:
a[0] = "one"
a[1] = "two"
a[3] = "three"
*/
a = array_values(a);
/* Now we've got:
a[0] = "one"
a[1] = "two"
a[2] = "three"
*/
?>
michiel ed thalent nl
19.06.2010 2:04
Update, if you use SORT_NUMERIC on this kind of filtering it will be significantly faster.
However the array_flip method still is twice as fast.
Anonymous
16.06.2010 14:46
It's often faster to use a foreache and array_keys than array_unique:

    <?php

    $max
= 1000000;
   
$arr = range(1,$max,3);
   
$arr2 = range(1,$max,2);
   
$arr = array_merge($arr,$arr2);

   
$time = -microtime(true);
   
$res1 = array_unique($arr);
   
$time += microtime(true);
    echo
"deduped to ".count($res1)." in ".$time;
   
// deduped to 666667 in 32.300781965256

   
$time = -microtime(true);
   
$res2 = array();
    foreach(
$arr as $key=>$val) {   
       
$res2[$val] = true;
    }
   
$res2 = array_keys($res2);
   
$time += microtime(true);
    echo
"<br />deduped to ".count($res2)." in ".$time;
   
// deduped to 666667 in 0.84372591972351

   
?>
regeda at inbox dot ru
12.04.2010 17:11
recursive array unique for multiarrays

<?php
function super_unique($array)
{
 
$result = array_map("unserialize", array_unique(array_map("serialize", $array)));

  foreach (
$result as $key => $value)
  {
    if (
is_array($value) )
    {
     
$result[$key] = super_unique($value);
    }
  }

  return
$result;
}
?>
brendel at krumedia dot de
24.02.2010 20:47
Prior to 5.2.9 you may create a list of unique objects this way:

<?php
for (; ; ) {
 
// ...
 
$uniqueObjectList[spl_object_hash($myObject)] = $myObject;
}
?>
amri [ at t] dhstudio dot eu
18.12.2009 11:36
I searched how to show only the duplicate elements from array, but failed.
Here is my solution:

<?php
function arrayDuplicate($array)
{
return
array_unique(array_diff_assoc($array1,array_unique($array1)));
};
?>

Example:
<?php
$arr1
= array('foo', 'bar', 'xyzzy', '&', 'xyzzy',
'baz', 'bat', '|', 'xyzzy', 'plugh',
'xyzzy', 'foobar', '|', 'plonk', 'xyzzy',
'apples', '&', 'xyzzy', 'oranges', 'xyzzy',
'pears','foobar');

$result=arrayDuplicate($arr1);
print_r($result);exit;
?>

Output:

Array
(
[4] => xyzzy
[12] => |
[16] => &
[21] => foobar
)
Youssef Omar
16.12.2009 20:09
This is how to merge 2 comma separated lists with unique value only.

<?php
  $list1
= "4444, 5555, 6666";
 
$list2 = "4444, 5555, 7777";

 
// combine both lists with unique values only
 
$list3 = implode("," , array_unique(array_merge(explode(",",$list1),explode(",", $list2))));

  echo
$list3;
?>

The result is: 4444,5555,6666,7777
macnimble at gmail dot com
8.09.2009 17:24
I'm not sure why you'd use any kind of loop to get the duplicates in an array. Here's a handy little function which does exactly that using some of PHP's other array_* functions.

<?php
function array_not_unique( $a = array() )
{
  return
array_diff_key( $a , array_unique( $a ) );
}
?>

Some arrays for testing:

<?php
$person
= array();
$person[1] = "person_1";
$person[2] = "person_2";
$person[3] = "person_3";
$person[4] = "person_4";
$person[5] = "person_5";
$person[6] = "person_2"; # DUPE
$person[7] = "person_4"; # DUPE
$person[8] = "person_4"; # DUPE
echo '<pre>',print_r(array_not_unique($person),1),'</pre>';
$person = array();
$person[] = 1;
$person[] = 2;
$person[] = 3;
$person[] = 4;
$person[] = 5;
$person[] = 2; # DUPE
$person[] = 4; # DUPE
$person[] = 4; # DUPE
echo '<pre>',print_r(array_not_unique($person),1),'</pre>';
?>

Output:
Array
(
    [6] => person_2
    [7] => person_4
    [8] => person_4
)

Array
(
    [5] => 2
    [6] => 4
    [7] => 4
)

Hope it helps.
--Bill
Wolfgang "DarkoNeko" ten Weges
1.07.2009 18:05
array_unique() is case-sensitive. If you need a case insensitive version, you better use something like this :

$f = create_function('$a,$b', 'return (strtolower($a) > strtolower($b)?1:-1);');
usort( $your_array, $f );
steve at visual77 dot com
27.05.2009 1:41
One way to use array_unique() to handle the multidimensional array issue is to use an md5 hash of the serialized array as the key. I've seen some solutions listed here that stored the serialized string, but that requires unserialization, and moving data back and forth between two states for little reason is just a bad idea. Instead, you could try this method:

<?php
$values
= array();

foreach(
$data as $d) {
   
$values[md5(serialize($d))] = $d;
}

sort($values);
?>

This will serialize and hash the value, and store the value with the hash as they key. This will ensure that each piece is only stored once, as the second attempt to store will just overwrite the first attempt with identical data.

The sort() at the end is a bit unnecessary, but I had to use it on my project, because the function I was passing the array to couldn't handle keys that weren't valid XML node names (and some md5 hash strings will start with numbers, which is invalid for XML).
dirk dot avery a t gmail
30.04.2009 17:45
Although array_unique is not intended to work with multi-dimensional arrays, it does on 5.2.9.  However, it does not for 5.2.5.  Beware.
Ultimater at gmail dot com
21.04.2009 3:26
Let's say you have
<?php
$v
=array("blue","blue","blue","blue");
if(
$v[0]==$v[1] && $v[1]==$v[2] && $v[2]==$v[3])
echo
"Y"; else echo "N";//Y
?>

It works but the if-statement gets a bit messy if the number of array elements gets massive.
I find it is easier to use array_unique like so:
<?php
$v
=array("blue","blue","blue","blue");
echo
sizeof(array_unique($v))==1?"Y":"N";//Y
?>
inithello at gmail dot com
12.03.2009 8:47
I noticed there was no way to tell array_unique() to ignore certain duplicated keys, so I wrote the following. I imagine there's half a dozen more efficient ways to do this, but here goes:

<?php
$array
= array('foo', 'bar', 'xyzzy', '&', 'xyzzy',
              
'baz', 'bat', '|', 'xyzzy', 'plugh',
              
'xyzzy', 'foobar', '|', 'plonk', 'xyzzy',
              
'apples', '&', 'xyzzy', 'oranges', 'xyzzy',
              
'pears');

$ignore_values = array('|', '&');

print_r(make_unique($array, $ignore_values));

function
make_unique($array, $ignore)
{
    while(
$values = each($array))
    {
        if(!
in_array($values[1], $ignore))
        {
           
$dupes = array_keys($array, $values[1]);
            unset(
$dupes[0]);
            foreach(
$dupes as $rmv)
            {
                unset(
$array[$rmv]);
            }           
        }
    }
    return
$array;
}
?>
OUTPUT:
Array
(
    [0] => foo
    [1] => bar
    [2] => xyzzy
    [3] => &
    [5] => baz
    [6] => bat
    [7] => |
    [9] => plugh
    [11] => foobar
    [12] => |
    [13] => plonk
    [15] => apples
    [16] => &
    [18] => oranges
    [20] => pears
)
serg dot podtynnyi at gmail dot com
6.02.2009 20:21
//Remove duplicates from a text files and dump result in one file for example: emails list, links list etc

<?php

$data1
= file("data1.txt");
$data2 = file("data2.txt");

file_put_contents('unique.txt', implode('', array_unique(array_merge($data1,$data2))));
?>
jusvalceanu - SPAM at SPAM - yahoo dot com
6.11.2008 11:23
so .... my problem was multidimensional sort.

<?php
      $new
= array();
     
$exclude = array("");
      for (
$i = 0; $i<=count($attribs)-1; $i++) {
         if (!
in_array(trim($attribs[$i]["price"]) ,$exclude)) { $new[] = $attribs[$i]; $exclude[] = trim($attribs[$i]["price"]); }
      }

?>

Array $attribs is an array contaning arrays. Each array in the $attrib array consists in multiple fields (ex: name, lenght, price, etc.) to be more simpler in speech think that $attrib is the array resulted by a search sql query done by a visitator on your online shoopping website ... (so ... each array in the $attrib is a product :P) if you want to sort only the uniq results use the above or use this:

<?php
 
  
/* Our Array of products */
  
$attribs[] = array(
                          
"name"         => "Test Product 1",
                          
"length"     => "42 cm",
                          
"weight"     => "0,5 kg",
                          
"price"     => "10 $",
                          
"stock"     => "100",
                        );

  
$attribs[] = array(
                          
"name"         => "Test Product 2",
                          
"length"     => "42 cm",
                          
"weight"     => "1,5 kg",
                          
"price"     => "10 $",
                          
"stock"     => "200",
                        );

   
/* The nice stuff */

     
$new = array();
     
$exclude = array("");
      for (
$i = 0; $i<=count($attribs)-1; $i++) {
         if (!
in_array(trim($attribs[$i]["price"]) ,$exclude)) { $new[] = $attribs[$i]; $exclude[] = trim($attribs[$i]["price"]); }
      }
     
     
print_r($new); // $new is our sorted array

?>

Have fun tweaking this ;)) i know you will ;))

From Romania With Love
florian at box dot net
8.10.2008 10:29
I came across one limitation of array_unique: it doesn't work properly if you have arrays inside your main array.

The reason is that to compare two values, the function tests if (string) $value1 == (string) $value2. So if $value1 and $value2 are both arrays, the function will evaluate the test to 'Array' == 'Array', and decide that the $values are repeated even if the arrays are different.

So a work around is to find a better conversion of an array to a string, which can be done with json:

<?php
print "define an array with repeated scalar '1' and repeated 'array(1)':";
$a_not_unique = array(
   
'a' => 1,
   
'b' => 1,
   
'c' => 2,
   
'd' => array(1),
   
'e' => array(1),
   
'f' => array(2),
);
print_r($a_not_unique);

print
"try to use simply array_unique, which will not work since it exludes 'array(2)':";
$a_unique_wrong = array_unique($a_not_unique);
print_r($a_unique_wrong);

print
"convert to json before applying array_unique, and convert back to array, which will successfully keep 'array(2)':";
$a_unique_right = $a_not_unique;
array_walk($a_unique_right, create_function('&$value,$key', '$value = json_encode($value);'));
$a_unique_right = array_unique($a_unique_right);
array_walk($a_unique_right, create_function('&$value,$key', '$value = json_decode($value, true);'));
print_r($a_unique_right);
?>

Results:
define an array with repeated scalar '1' and repeated 'array(1)':
Array
(
    [a] => 1
    [b] => 1
    [c] => 2
    [d] => Array
        (
            [0] => 1
        )

    [e] => Array
        (
            [0] => 1
        )

    [f] => Array
        (
            [0] => 2
        )
)

try to use simply array_unique, which will not work since it exludes 'array(2)':
Array
(
    [a] => 1
    [c] => 2
    [d] => Array
        (
            [0] => 1
        )
)

convert to json before applying array_unique, and convert back to array, which will successfully keep 'array(2)':
Array
(
    [a] => 1
    [c] => 2
    [d] => Array
        (
            [0] => 1
        )

    [f] => Array
        (
            [0] => 2
        )
)
quecoder at gmail
26.08.2008 7:30
another method to get unique values is :

<?php
$alpha
=array('a','b','c','a','b','d','e','f','f');

$alpha= array_keys(array_count_values($alpha));

print_r($alpha);
?>

Output:
Array ( [0] => a [1] => b [2] => c [3] => d [4] => e [5] => f )
soapergem at gmail dot com
14.08.2008 23:39
Here's another solution for returning an array that only includes repeated values. There is one given below but it only works on numerically indexed arrays; this one is more comprehensive since I used the foreach iterator. Also, this one preserves keys--in that the returned result contains a distinct list of repeats (storing only the first instance it encounters of each duplicate value).

<?php

function array_repeated($array)
{
    if ( !
is_array($array) ) {
        return
false;
    }
   
   
$duplicates = array();
    foreach (
$array as $key => $val ) {
       
end($array);
       
$k = key($array);
       
$v = current($array);
       
        while (
$k !== $key ) {
            if (
$v === $val ) {
               
$duplicates[$key] = $v;
                                break;
            }
           
           
$v = prev($array);
           
$k = key($array);
        }
    }
   
    return
$duplicates;
}

?>
Dorphalsig
28.07.2008 18:47
I had a problem with array_unique and multidimensional arrays ... Maybe there's a better way to do this, but this will work for any dimensional arrays.

<?php
function arrayUnique($myArray)
{
    if(!
is_array($myArray))
           return
$myArray;

    foreach (
$myArray as &$myvalue){
       
$myvalue=serialize($myvalue);
    }

   
$myArray=array_unique($myArray);

    foreach (
$myArray as &$myvalue){
       
$myvalue=unserialize($myvalue);
    }

    return
$myArray;

}
?>
ali at zkurd dot org
19.06.2008 10:41
a lot of people create functions just to fix a notice error about an undefined index and removes blank array value.

why not using foreach instead of the for loop?

example:
<?php
foreach ($arrayname as $key => $value) {
   
//do what you want with $value withaout index stress
}
?>
PHP Expert
14.04.2008 14:34
case insensitive for PHP v4.x and up.

<?php

function in_iarray($str, $a){
foreach(
$a as $v){
if(
strcasecmp($str, $v)==0){return true;}
}
return
false;
}

function
array_iunique($a){
$n = array();
foreach(
$a as $k=>$v){
if(!
in_iarray($v, $n)){$n[$k]=$v;}
}
return
$n;
}

$input = array("aAa","bBb","cCc","AaA","ccC","ccc","CCC","bBB","AAA","XXX");
$result = array_iunique($input);
print_r($result);

/*
Array
(
    [0] => aAa
    [1] => bBb
    [2] => cCc
    [9] => XXX
)
*/
?>
Ray dot Paseur at SometimesUsesGmail dot com
2.03.2008 4:46
I needed to identify email addresses in a data table that were replicated, so I wrote the array_not_unique() function:

<?php

function array_not_unique($raw_array) {
   
$dupes = array();
   
natcasesort($raw_array);
   
reset ($raw_array);

   
$old_key    = NULL;
   
$old_value    = NULL;
    foreach (
$raw_array as $key => $value) {
        if (
$value === NULL) { continue; }
        if (
$old_value == $value) {
           
$dupes[$old_key]    = $old_value;
           
$dupes[$key]        = $value;
        }
       
$old_value    = $value;
       
$old_key    = $key;
    }
return
$dupes;
}

$raw_array     = array();
$raw_array[1]    = 'abc@xyz.com';
$raw_array[2]    = 'def@xyz.com';
$raw_array[3]    = 'ghi@xyz.com';
$raw_array[4]    = 'abc@xyz.com'; // Duplicate

$common_stuff    = array_not_unique($raw_array);
var_dump($common_stuff);
?>
php_array_unique [at] peterwarnock.com
19.12.2007 20:20
To clarify the note above Example #1, the function appears to cast the elements to strings for comparison and then return the type of the first unique element encountered. 

<?php
$input
= array(0, 2, "2", 3, "9", 9);
$result = array_unique($input);
var_dump($result);
?>

array(4) {
  [0]=>
  int(0)
  [1]=>
  int(2)
  [3]=>
  int(3)
  [4]=>
  string(1) "9"
}
mnbayazit
28.10.2007 23:18
case insensitive

<?php
function array_iunique($array) {
    return
array_intersect_key($array,array_unique(
                
array_map(strtolower,$array)));
}
?>
array_unique_FULL
11.10.2007 9:58
<?php
function array_unique_FULL($array) {
  foreach(
$array as $k => $v) {
    if (
is_array($v)) {
     
$ret = array_unique_FULL(array_merge($ret, $v));
    } else {
     
$ret[$k] = $v;
    }
  }
//for

 
return array_unique($ret);
}
?>

Array
(
    [0] => js/pt.js
    [1] => js/selectfile.js
    [2] => js/pt.js
    [3] => js/proyecto.js
    [4] => Array
        (
            [0] => Array
                (
                    [0] => js/selectfile.js
                    [1] => js/selectfile.js
                    [2] => js/y otro mas.js
                )

            [1] => q se yo
        )

)

go array_unique_FULL()!!!!

Array
(
    [0] => js/pt.js
    [1] => js/selectfile.js
    [3] => js/proyecto.js
    [6] => js/y otro mas.js
    [5] => q se yo
)
mew at world dot end dot org
2.10.2007 9:05
Smaller version for PHP5

<?php

# array array_unique_save (array array [, bool preserve_keys] )
function array_unique_save ($a, $pk = true) {
   
$a = array_diff_key($a, array_unique($a));
    return (
$pk ? $a : array_values($a));
}

?>
logicearth at gmail dot com
17.09.2007 1:57
Should have thought of this sooner. x.x

<?php

function array_unique_save_php4 ($a, $pk = true) {
   
$t = array_keys(array_unique($a));
    foreach (
$t as $k) { unset($a[$k]); }
    return (
$pk ? $a : array_values($a));
}

?>
xjazey at hotmail dot com
11.09.2007 20:50
This is a solution to remove duplicate values from an array

<?php

$array
[0] = "Yellow";
$array[1] = "Green";
$array[2] = "Yellow";
$array[3] = "Blue";
$array[4] = "Yellow";

$array = array_keys(array_flip($array));

//$array will output Yellow Green Blue

?>
tsikano at attglobal dot net
22.08.2007 1:20
Suggestion for being able to use array_unique on array of arrays/objects:

<?php
foreach ($arrayOfArrays as $key=>$value) {
 
$arrayOfArrays[$key] = "'" . serialize($value) . "'";
}
$arrayOfArrays = array_unique($arrayOfArrays);
foreach (
$arrayOfArrays as $key=>$value) {
 
$arrayOfArrays[$key] = unserialize(trim($value, "'"));
}
?>
webmaster at jukkis dot net
30.07.2007 13:08
Another way to 'unique column' an array, in this case an array of objects:
Keep the desired unique column values in a static array inside the callback function for array_filter.

Example:
<?php
/* example object */
class myObj {
  public
$id;
  public
$value;
  function
__construct( $id, $value ) {
   
$this->id = $id;
   
$this->value = $value;
  }
}

/* callback function */
function uniquecol( $obj ) {
  static
$idlist = array();

  if (
in_array( $obj->id, $idlist ) )
    return
false;

 
$idlist[] = $obj->id;
  return
true;   
}

/* a couple of arrays with second array having an element with same id as the first */
$list  = array( new myObj( 1, ), new myObj( 2, 100 ) );
$list2 = array( new myObj( 1, 10 ), new myObj( 3, 100 ) );
$list3 = array_merge( $list, $list2 );

$unique = array_filter( $list3, 'uniquecol' );
print_r( $list3 );
print_r( $unique );

?>

In addition, use array_merge( $unique ) to reindex.
snoyes+php at gmail dot com
11.07.2007 18:08
Another way to get unique objects/arrays:
<?php
function my_array_unique($array) {
    return
array_intersect_key($array, array_unique(array_map('serialize', $array)));
}
?>
laurynas dot butkus at gmail dot com
23.05.2007 13:22
This one would work with objects and arrays also.

<?php
function my_array_unique($array, $keep_key_assoc = false)
{
   
$duplicate_keys = array();
   
$tmp         = array();       

    foreach (
$array as $key=>$val)
    {
       
// convert objects to arrays, in_array() does not support objects
       
if (is_object($val))
           
$val = (array)$val;

        if (!
in_array($val, $tmp))
           
$tmp[] = $val;
        else
           
$duplicate_keys[] = $key;
    }

    foreach (
$duplicate_keys as $key)
        unset(
$array[$key]);
       
    return
$keep_key_assoc ? $array : array_values($array);
}
?>
danny at lostsockdesign dot com dot au
13.04.2007 3:44
An updated version of webcreators script that fixes a notice error about an undefined index and removes blank array value.

<?php
function my_array_unique($from) {
    for (
$i=count($from)-1;$i>1;$i--) {
       
$last = $from[$i];
       
$from[$i] = false;
        if (!
in_array($last,$from)) {
           
$from[$i]=$last;  
        }
    }
   
$from = array_unique($from);
   
$from = array_slice($from,0,count($from)-1);
    return
$from;
}
?>
n@cho NOSPAM cofrepuntonet
13.12.2006 11:45
What if I only want the duplicated items, not the unique ones?

I tried to do it by using array_diff of an array and its unique, but it did not work (any help?); so I made this function with a relatively good efficiency:

<?php
function array_repeated($array) {

    if(!
is_array($array)) return false;
   
$repeated_values = Array();
   
$array_unique = array_unique($array);
    if(
count($array)-count($array_unique)) {
        for(
$i=0;$i<count($array);$i++) {
            if(!
array_key_exists($i, $array_unique)) $repeated_values[] = $array[$i];
        }
    }
    return
$repeated_values;
}
?>

This function is based on the behaviour of the array_unique function that mantains the indexes of the array when deleting the item.
n@cho NOSPAM cofrepuntonet
13.12.2006 11:26
Note that array_unique preserves the keys, even if the array is not associative:

$values = Array("john@hotmail.com", "peter@hotmail.com", "will@hotmail.com", "john@hotmail.com", "laura@hotmail.com", "mariah@hotmail.com");
echo "<br>".count($values)." values.<br>";
var_dump($values);

$unique_values = array_unique($values);
echo "<br>".count($unique_values)." unique values.<br>";
var_dump($unique_values);

RESULT:

6 values.
array(6) {
  [0]=>
  string(16) "john@hotmail.com"
  [1]=>
  string(17) "peter@hotmail.com"
  [2]=>
  string(16) "will@hotmail.com"
  [3]=>
  string(16) "john@hotmail.com"
  [4]=>
  string(17) "laura@hotmail.com"
  [5]=>
  string(18) "mariah@hotmail.com"
}

5 unique values.
array(5) {
  [0]=>
  string(16) "john@hotmail.com"
  [1]=>
  string(17) "peter@hotmail.com"
  [2]=>
  string(16) "will@hotmail.com"
  [4]=>
  string(17) "laura@hotmail.com"
  [5]=>
  string(18) "mariah@hotmail.com"
}

$unique_values[3] is missing. Use array_merge or array_values if you need the index to be linear.
arr1
1.11.2006 17:59
Just to note that array_unique, treats null values as none unique values. So if your using array_unique to detect duplicate values it will also detect multiple null values.
Ome_Henk
27.10.2006 21:16
For people looking at the flip flip method for getting unique values in a simple array. This is the absolute fastest method:

<?php
$unique
= array_keys(array_flip($array));
?>

It's marginally faster as:
<?php
$unique
= array_merge(array_flip(array_flip($array)));
?>

And it's marginally slower as:
<?php
$unique array_flip
(array_flip($array)); // leaves gaps
?>

It's still about twice as fast or fast as array_unique.

This tested on several different machines with 100000 random arrays. All machines used a version of PHP5.
geuis dot teses at gmail dot com
9.10.2006 19:27
Here's the shortest line of code I could find/create to remove all duplicate entries from an array and then reindex the keys.

<?php

// Fruits, vegetables, and other food:
$var = array('apple','banana','carrot','cat','dog','egg','eggplant','fish');

$var = array_values(array_unique($var));
?>
keneks at gmail dot com
30.09.2006 16:01
Taking the advantage of array_unique, here is a simple function to check if an array has duplicate values.

It simply compares the number of elements between the original array and the array_uniqued array.

<?php
function array_search_dups($array)
{
   
$dup_array = $array;
   
$dup_array = array_unique($dup_array);
    if(
count($dup_array) != count($array))
    {
        return
TRUE;
    }
    else
    {
        return
FALSE;
    }
}
?>
pulsarkowy at NOSPAM dot gmail dot com
13.09.2006 13:30
This function below will remove multiple values from array, remove 'empty' fields an also count how many times the given value occured.

it's rather slow and not 'elegant' but works.

usage:
<?php
$myarray
= my_array_unique($myarray);
?>

in return it produces an 3 fields array:
1st is index number, 2nd is the value, 3rd is counter.

<?php
function my_array_unique($tablica)
{

$tnum=count($tablica);
$i=1;
$k=1;
$t[1]['product']="";
$t[1]['count']=1;
while(
$i<=$tnum) {
  if (!
array_multi_search($tablica[$i], $t)) {
   
$t[$k]['product']=$tablica[$i];
   
$t[$k]['count']=1;
   
$k++;
  }
  else {
   
$y=1;
    while (
$y<=count($t)) {
      if (
$t[$y]['product']==$tablica[$i])
       
$t[$y]['count']++;
     
$y++;
    }

  }
 
$i++;


$tablica=$t;
return
$tablica;
}
?>

the function uses another function that i've found on the php.net site (i'm posting it only for informational reasons - i can't remember who wrote it):

<?php
function array_multi_search( $p_needle, $p_haystack )
   {
       if( !
is_array( $p_haystack ) )
       {
           return
false;
       }

       if(
in_array( $p_needle, $p_haystack ) )
       {
           return
true;
       }

       foreach(
$p_haystack as $row )
       {
           if(
array_multi_search( $p_needle, $row ) )
           {
               return
true;
           }
       }

       return
false;
   }
?>

[EDIT BY danbrown AT php DOT net: The array_multi_search() function was originally written by 'czeslaw' and posted to the in_array() function manual entry on 18 February, 2006.]
a dot fotoglidis at 7mbit dot net
24.07.2006 5:25
In addition to brettz9's remove_dups:

This one will actually take a multi-dimensional array and return it minus the duplicates in regard to the specified element of the inner arrays.

<?php
/*
  Initialising new array to the first element of the given array.
  Check whether current element in initial array has already been added to new array.
  If yes break to save us some time. If no, then add current element to new array.
*/

function remove_dups($array, $row_element) {   
   
$new_array[0] = $array[0];
    foreach (
$array as $current) {
       
$add_flag = 1;
        foreach (
$new_array as $tmp) {
            if (
$current[$row_element]==$tmp[$row_element]) {
               
$add_flag = 0; break;
            }
        }
        if (
$add_flag) $new_array[] = $current;
    }
    return
$new_array;
}
// end function remove_dups
?>

______________________________________________
EXAMPLE

<?php
    $array
[0] = array('Charles','Wade',233);
   
$array[1] = array('Charles','Watson',234);
   
$array[2] = array('Tom','Wade',235);
   
$array = remove_dups($array,0);
?>

The above example will output:
Array
(
    [0] => Array ([0] => 'Charles' [1] => 'Wade' [2] => 233)
    [1] => Array ([0] => 'Tom' [1] => 'Wade' [2] => 235)
)

<?php
remove dups
($array,1);
?>

will output:
Array
(
    [0] => Array ([0] => 'Charles' [1] => 'Wade' [2] => 233)
    [1] => Array ([1] => 'Charles' [1] => 'Watson' [2] => 234)
)

At each case it removes all inner arrays that have a duplicate in the specified position and keeps the first inner array only.
uditsawhney at yahoo dot com
15.07.2006 21:14
<?php

//Fn for array_unique column-wise for multi-dimensioanl array without losing keys | Start
function array_uniquecolumn($arr)
{
   
$rows   = sizeof($arr);
   
$columns = sizeof($arr[0]);
   
   
$columnkeys = array_keys($arr[0]);
   

    for(
$i=0; $i<$columns; $i++)
    {
        for(
$j=0;$j<$rows;$j++)
        {
            for(
$k = $j+1; $k<$rows; $k++)
            {
                if(
$arr[$j][$columnkeys[$i]] == $arr[$k][$columnkeys[$i]])
                   
$arr[$k][$columnkeys[$i]] = "";       
            }
        }
   
    }

return (
$arr);

}
//Fn for array_unique column-wise for multi-dimensioanl array without losing keys | Stop

$arrUGCourse[]= array(  "CTR" => "1",

                       
"UGCOURSE"=>"ABC",

                       
"TSINITIATE"=>"540",

                       
"COUNT"=>"34",

                       
"ENTRY_DT"=>"2006-05-01",

                       
"CUMULATIVE"=> 44);

 

$arrUGCourse[]= array(  "CTR" => "2",

                       
"UGCOURSE"=>"ABC",

                       
"TSINITIATE"=>"5401",

                       
"COUNT"=>"341",

                       
"ENTRY_DT"=>"2006-05-11",

                       
"CUMULATIVE"=> 44);

print_r(array_uniquecolumn($arrUGCourse));

?>
davin at baragiotta dot org
20.04.2006 0:52
I used the code submitted by "agarcia" regarding multi-dimensional arrays but keys with no data were still there. I've just added a line to completely unset the redondant part of the array so it is now acting like array_unique.

<?php
function remove_dup($matriz) {
  
$aux_ini=array();
  
$entrega=array();
   for(
$n=0;$n<count($matriz);$n++) {
     
$aux_ini[]=serialize($matriz[$n]);
   }
  
$mat=array_unique($aux_ini);
   for(
$n=0;$n<count($matriz);$n++) {
     
$entrega[]=unserialize($mat[$n]);
   }
   foreach (
$entrega as $key => $row){
      if (!
is_array($row)) { unset($entrega[$key]); }
   }
   return
$entrega;
}
?>

Thanks!

Davin Baragiotta
MoD
14.04.2006 18:02
The shortest way i found to remove duplicate array from a column,
For example if you parse Multiple XML sources, you can remove duplicate items that contain the same link.

<?PHP
function        remove_duplicate($array, $field)
{
  foreach (
$array as $sub)
   
$cmp[] = $sub[$field];
 
$unique = array_unique($cmp);
  foreach (
$unique as $k => $rien)
   
$new[] = $array[$k];
  return
$new;
}
?>
agarcia at rsn dot com dot co
31.03.2006 22:41
This is a script for multi_dimensional arrays

<?php
function remove_dup($matriz) {
   
$aux_ini=array();
   
$entrega=array();
    for(
$n=0;$n<count($matriz);$n++)
    {
       
$aux_ini[]=serialize($matriz[$n]);
    }
   
$mat=array_unique($aux_ini);
    for(
$n=0;$n<count($matriz);$n++)
    {
       
           
$entrega[]=unserialize($mat[$n]);
       
    }
    return
$entrega;
}
?>
brettz9
9.03.2006 9:51
If you have a multi-dimensional array and wish to remove duplicates from a particular "column" as well as the corresponding values in the other "columns", you might find the following helpful.

<?php
function remove_dups($array, $index) {
   
$array_count = count($array);
   
$array_count_inner = count($array[$index]);
    for (
$i=0; $i<$array_count_inner; $i++) {
        for (
$j=$i+1; $j<$array_count_inner; $j++) {
            if (
$array[$index][$i]==$array[$index][$j]) {
                for (
$k=0; $k<$array_count; $k++) {
                    unset(
$array[$k][$i]);
                }
// end for   
           
} // end if
       
} // end for   
   
} // end for
   
return $array;
}
// end function remove_dups
?>
mcmeijer at yahoo dot com
27.01.2006 14:18
This is a recursive arrayUnique function for arrays of any dimension. (tested with 4-dimensional array)
The line '$newArray=deleteEmpty($newArray);' is optional and removes empty keys and values
<?php
function arrayUnique($myArray)
    {
   
$newArray = Array();
    if (
is_array($myArray))
        {
        foreach(
$myArray as $key=>$val)
            {
            if (
is_array($val))
                {
               
$val2 = arrayUnique($val);
                }
            else
                {
               
$val2 = $val;
               
$newArray=array_unique($myArray);
               
$newArray=deleteEmpty($newArray);
                break;
                }
            if (!empty(
$val2))
                {
               
$newArray[$key] = $val2;
                }
            }
        }
    return (
$newArray);
    }

function
deleteEmpty($myArray)
    {
   
$retArray= Array();
    foreach(
$myArray as $key=>$val)
        {
        if ((
$key<>"") && ($val<>""))
            {
           
$retArray[$key] = $val;
            }
        }
    return
$retArray;
    }
?>
memandeemail at gmail dot com
3.01.2006 19:47
Problem:
I have loaded an array with the results of a database
query.  The Fields are 'FirstName' and 'LastName'.

I would like to find a way to contactenate the two
fields, and then return only unique values for the
array.  For example, if the database query returns
three instances of a record with the FirstName John
and the LastName Smith in two distinct fields, I would
like to build a new array that would contain all the
original fields, but with John Smith in it only once.
Thanks for: Colin Campbell

Solution:

<?php
/**
 * The same thing than implode function, but return the keys so
 *
 * <code>
 * $_GET = array('id' => '4587','with' => 'key');
 * ...
 * echo shared::implode_with_key('&',$_GET,'='); // Resultado: id=4587&with=key
 * ...
 * </code>
 *
 * @param string $glue Oque colocar entre as chave => valor
 * @param array $pieces Valores
 * @param string $hifen Separar chave da array do valor
 * @return string
 * @author memandeemail at gmail dot com
 */
function implode_with_key($glue = null, $pieces, $hifen = ',') {
 
$return = null;
  foreach (
$pieces as $tk => $tv) $return .= $glue.$tk.$hifen.$tv;
  return
substr($return,1);
}

/**
 * Return unique values from a tree of values
 *
 * @param array $array_tree
 * @return array
 * @author memandeemail at gmail dot com
 */
function array_unique_tree($array_tree) {
 
$will_return = array(); $vtemp = array();
  foreach (
$array_tree as $tkey => $tvalue) $vtemp[$tkey] = implode_with_key('&',$tvalue,'=');
  foreach (
array_keys(array_unique($vtemp)) as $tvalue) $will_return[$tvalue] = $array_tree[$tvalue];
  return
$will_return;
}

$problem = array_fill(0,3,
array(
'FirstName' => 'John', 'LastName' => 'Smith')
);

$problem[] = array('FirstName' => 'Davi', 'LastName' => 'S. Mesquita');
$problem[] = array('FirstName' => 'John', 'LastName' => 'Tom');

print_r($problem);

print_r(array_unique_tree($problem));
?>
webcreator at centrum dot cz
28.10.2005 13:25
array_unique function starts its comparation from beginning and pop the key off if there is more values inside array. The last one remains. But i needed to hold priority of the order of values and let the first one in.

Here is my easy solution:

<?php
function my_array_unique($from)
{
for (
$i=count($from);$i>1;$i--)
    {
   
$last = $from[$i];
   
$from[$i] = "";
    if (!
in_array($last,$from))
       
$from[$i]=$last;   
    }
return
array_unique($from);
}

# One empty value remains in array.
# But its very easy to separate it while using output array.
?>
kenrbnsn at rbnsn dot com
27.09.2005 6:09
Yet another Array_Unique for multi-demensioned arrays. I've only tested this on two-demensioned arrays, but it could probably be generalized for more, or made to use recursion.

This function uses the serialize, array_unique, and unserialize functions to do the work.

<?php
function multi_unique($array) {
    foreach (
$array as $k=>$na)
       
$new[$k] = serialize($na);
   
$uniq = array_unique($new);
    foreach(
$uniq as $k=>$ser)
       
$new1[$k] = unserialize($ser);
    return (
$new1);
}
?>
passtschu AT freenet DOT de
21.09.2005 16:20
array_unique for multidimensional arrays. similar to the DISTINCT in SQL function.
the function can group, sum and count keys

<?PHP
/*
$array - nothing to say
$group_keys - columns which have to be grouped - can be STRING or ARRAY (STRING, STRING[, ...])
$sum_keys - columns which have to be summed - can be STRING or ARRAY (STRING, STRING[, ...])
$count_key - must be STRING - count the grouped keys
*/
function array_distinct ($array, $group_keys, $sum_keys = NULL, $count_key = NULL){
  if (!
is_array ($group_keys)) $group_keys = array ($group_keys);
  if (!
is_array ($sum_keys)) $sum_keys = array ($sum_keys);

 
$existing_sub_keys = array ();
 
$output = array ();

  foreach (
$array as $key => $sub_array){
   
$puffer = NULL;
   
#group keys
   
foreach ($group_keys as $group_key){
     
$puffer .= $sub_array[$group_key];
    }
   
$puffer = serialize ($puffer);
    if (!
in_array ($puffer, $existing_sub_keys)){
     
$existing_sub_keys[$key] = $puffer;
     
$output[$key] = $sub_array;
    }
    else{
     
$puffer = array_search ($puffer, $existing_sub_keys);
     
#sum keys
     
foreach ($sum_keys as $sum_key){
        if (
is_string ($sum_key)) $output[$puffer][$sum_key] += $sub_array[$sum_key];
      }
     
#count grouped keys
     
if (!array_key_exists ($count_key, $output[$puffer])) $output[$puffer][$count_key] = 1;
      if (
is_string ($count_key)) $output[$puffer][$count_key]++;
    }
  }
  return
$output;
}
?>
muddmonkey@harveyMcoldotedu
17.08.2005 22:44
If you're doing numeric arrays etc. I found flip-flip to work much better than array_unique:

<?PHP
   
function microtime_float(){ //timing
      
list($usec, $sec) = explode(" ", microtime());
       return ((float)
$usec + (float)$sec);
    }

   
//make an arry and fill it up
   
$final=array();
    for(
$i=0;$i<50000;$i++){
       
$final[]=$i%13; //make sure there are some dupes
   
}
   
//try array unique
   
$start1 = microtime_float();
   
array_unique($final);
   
$stop1=microtime_float();
    echo(
$stop1-$start1.'<br>');
   
//try my flip-flip
   
$start2=microtime_float();
   
array_flip(array_flip($final));
   
$stop2=microtime_float();
    echo(
$stop2-$start2);
?>

Running this with only ints in the array (as above) I get runtimes such as:
1.6195669174194 (using unique)
0.017037868499756 (using flip flip)
which is two orders of magnitude faster!

Appending a string:
($final[]='test'.$i%13;)
gives:
0.42909598350525 (using unique)
0.023258924484253 (using flip-flip)
Which is not AS great, but still 20x faster than unique.

In both cases the flip-flip seems to use less memory than the unique.

Granted the flip-flip doesn't work for all cases, but if you're doing simple stuff like this, the flip-flip will give you better run times.

~JF
Christoph Ziegenberg
17.06.2005 20:44
If the array key is a string it might be important to keep it although the value is the same (as I need it at the moment). So I wrote a function which also returns array elements which have the same value but different string keys.

<?php
function array_unique_numeric ($arr)
{
   
$str = $int = array();
    foreach(
array_keys($arr) as $key) {
        ${(
is_int($key)?'int':'str')}[$key] = $arr[$key];
    }
    return
array_merge($str, array_unique($int));
}

// typical array after an array_merge()...
$array = array("a" => "green", "b" => "brown", "c" => "blue", "red", "d" => "green", "yellow", "red");

print_r(array_unique($array));
// Array
// (
//     [a] => green
//     [b] => brown
//     [c] => blue
//     [0] => red
//     [1] => yellow
// )

print_r(array_unique_numeric($array));
// Array
// (
//     [a] => green
//     [b] => brown
//     [c] => blue
//     [d] => green
//     [0] => red
//     [1] => yellow
// )
?>
memandeemail at gmail dot com
15.04.2005 22:46
<?php
/**
 * Removes duplicate keys from an array
 *
 * @param array $array
 * @return array
 */
function array_unique_key($array) {
   
$result = array();
    foreach (
array_unique(array_keys($array)) as $tvalue) {
       
$result[$tvalue] = $array[$tvalue];
    }
    return
$result;
}
?>
Ric
5.04.2005 18:44
A very simple way of getting rid of duplicate entries and re-indexing with key starting at 0:

<?php
    $temp
=array_unique($main);
   
$main=array_values($temp);
?>
trigger at e-mail dot ru
3.02.2005 11:53
Just a simple implementation for JavaScript:

<?php
function array_unique(thearray)
{
   
thearray.sort();
   
//reset($thearray);
   
newarray = new Array();
    for (
n=0;n<thearray.length;n++)
    {
       
unique=1;//by default
       
for(nn=0;nn<newarray.length;nn++)
            if (
thearray[n] == newarray[nn])
            {
               
unique=0;//already exists
               
break;
            }
        if(
unique)//dont exists
           
newarray.push(thearray[n]);
    }
    return
newarray;
 }
?>
lucas.bickel AT purplehaze DOT ch
26.10.2004 17:39
I quite like the following code for making multidimensional arrays unique:

<?php
foreach ($arrAddressList AS $key => $arrAddress) {
   
$arrAddressList[$key] = serialize($arrAddress);
}
$arrAddressList = array_unique($arrAdressList);
foreach (
$arrAddressList AS $key => $strAddress) {
   
$arrAddressList[$key] = unserialize($strAddress);
}
?>

This gets me a unique array while not minding wether the the original array contains arrays or just strings (or whatever...).
justin at redwiredesign dot com
14.09.2004 15:23
OK, so here's my version that maintains index integrity:

<?php
function array_unique($array)
{
   
$out = array();
   
   
//    loop through the inbound
   
foreach ($array as $key=>$value) {
       
//    if the item isn't in the array
       
if (!in_array($value, $out)) {
           
//    add it to the array
           
$out[$key] = $value;
        }
    }
   
    return
$out;
}
?>
wernerlistas at terra dot com dot br
16.06.2004 17:50
Following the code copies of a little function I've wrote that actually works with multidimensional arrays.
It also resets the array indexes.

<?php
if ( !function_exists( "arrayUnique" ) ){
    function
arrayUnique ( $rArray ){
       
$rReturn = array ();
        while ( list(
$key, $val ) = each ( $rArray ) ){
            if ( !
in_array( $val, $rReturn ) )
           
array_push( $rReturn, $val );
        }
        return
$rReturn;
    }
}
?>
csaba at alum dot mit dot edu
10.06.2004 4:17
The following is an efficient, adaptable implementation of array_unique which always retains the first key having a given value:

<?php
function array_unique2(&$aray) {
   
$aHash = array();
    foreach (
$aray as $key => &$val) if (@$aHash[$val]++) unset ($aray[$key]);
}
?>

It is also adaptable to multi dimensional arrays.  For example, if your array is a sequence of (multidimensional) points, then in place of @$aHash[$val]++ you could use @$aHash[implode("X",$val)]++
If you want to not have holes in your array, you can do an array_merge($aray) at the end.

Csaba Gabor
patrikG at home dot net
11.03.2004 16:05
If you need to have the keys of the duplicates in an array returned, you may find this function useful:

<?php
function unique_events($array){
   
//checks $array for duplicate values and returns an
        //array containing the keys of duplicates
   
$count= array_intersect_assoc($array, array_flip( array_count_values($array)));
    foreach(
$array as $key=>$value){
        if (
in_array($value,$count)){
           
$return[$value][]=$key;
        }
    }
    return
$return;
}
?>

Example:

Input:
Array
(
    [0] => 44
    [1] => 23
    [2] => 23
    [3] => 23
    [4] => 9
    [5] => 9
    [6] => 9
    [7] => 9
    [8] => 9
    [9] => 9
    [10] => 9
    [11] => 9
)

Function returns:
Array
(
    [23] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [9] => Array
        (
            [0] => 4
            [1] => 5
            [2] => 6
            [3] => 7
            [4] => 8
            [5] => 9
            [6] => 10
            [7] => 11
        )

)
bitmore.co.kr
20.02.2004 0:53
//Modify
Object Unique

<?php
   
class foo {
        var
$_name;
        var
$_age;
        function
foo($name,$age=NULL)    { $this->_name = $name; $this->_age = $age; }
       
//function get()        { return $this->_name; }
        //function set($name,$age=NULL)    { $this->_name = $name; $this->_age = $age; }
   
}

    function
DistinctOn ($obj, $item) {
       
$out = array();
       
$list = array();
        foreach (
$obj as $key=>$so) {
            if (!
in_array($so->$item, $list)) {
                echo
"key = $key,so = $so,item = $item,IFlist = ";print_r($list);echo "<br>";
               
$list[] = $so->$item;//迭
               
$out[$key] = $so;
            }
            echo
"Forlist = ";print_r($list);echo "<br>";
        }
        return
$out;
    }

   
$foo_obj[0] = new foo('tom',20);
   
$foo_obj[1] = new foo('paul',66);
   
$foo_obj[2] = new foo('tom',23);

   
$item = '_name';
   
$result = DistinctOn ($foo_obj, $item);

    while(list(
$k,$v) = each($result)) {
        print
"K = ";print_r($k);
        print
",V = ";print_r($v);
        print
"<br>";
    }
   
//key = 0,so = Object,item = _name,IFlist = Array ( ) ,Forlist = Array ( [0] => tom )
    //key = 1,so = Object,item = _name,IFlist = Array ( [0] => tom ) ,Forlist = Array ( [0] => tom [1] => paul )
    //Forlist = Array ( [0] => tom [1] => paul )
    //K = 0,V = foo Object ( [_name] => tom [_age] => 20 )
    //K = 1,V = foo Object ( [_name] => paul [_age] => 66 )

   
print "<br><br>";
   
$item = '_age';
   
$result = DistinctOn ($foo_obj, $item);
    while(list(
$k,$v) = each($result)) {
        print
"K = ";print_r($k);
        print
",V = ";print_r($v);
        print
"<br>";
    }

   
//key = 0,so = Object,item = _age,IFlist = Array ( ) ,Forlist = Array ( [0] => 20 )
    //key = 1,so = Object,item = _age,IFlist = Array ( [0] => 20 ) ,Forlist = Array ( [0] => 20 [1] => 66 )
    //key = 2,so = Object,item = _age,IFlist = Array ( [0] => 20 [1] => 66 ) ,
    //    Forlist = Array ( [0] => 20 [1] => 66 [2] => 23 )
    //K = 0,V = foo Object ( [_name] => tom [_age] => 20 )
    //K = 1,V = foo Object ( [_name] => paul [_age] => 66 )
    //K = 2,V = foo Object ( [_name] => tom [_age] => 23 )
?>

14.01.2004 14:23
this simple function is similar based on to the function unique_multi_array posted by tru at ascribedata dot com, but will work for objects rather than arrays. use 2d objects. Its eg useful to work with mysql queries since in recent versions, the DISTINCT option in mysql selects will only work when selecting a single (not more) row.

eg.
foo_obj[0]:  name: 'tom', age: '20'
foo_obj[1]:  name: 'paul', age: '66'
foo_obj[2]:  name: 'tom', age: '23'

foo_obj = DistinctOn ($foo_obj, $item) will return

foo_obj[0]:  name: 'tom', age: '20'
foo_obj[1]:  name: 'paul', age: '66'

<?php
function DistinctOn ($obj, $item) {
  
$out = array();
  
$list = array();
   foreach (
$obj as $key=>$so) {
       if (!
in_array($so->$item, $list)) {
          
$list[] = $so->$item;
          
$out[$key] = $so;
       }
   }
   return
$out;
}
?>
tru at ascribedata dot com
17.10.2003 1:40
Here's a function to make a multi-dimensional array have only DISTINCT values for a certain "column". It's like using the DISTINCT parameter on a SELECT sql statement.

<?php
function unique_multi_array($array, $sub_key) {
   
$target = array();
   
$existing_sub_key_values = array();
    foreach (
$array as $key=>$sub_array) {
        if (!
in_array($sub_array[$sub_key], $existing_sub_key_values)) {
           
$existing_sub_key_values[] = $sub_array[$sub_key];
           
$target[$key] = $sub_array;
        }
    }
    return
$target;
}
?>
kay_rules at yahoo dot com
24.05.2003 11:28
this function will return an array with unique value and proper key increment start from 0.

<?php
/*******************************/
function my_array_unique($somearray){
   
$tmparr = array_unique($somearray);
   
$i=0;
    foreach (
$tmparr as $v) {
       
$newarr[$i] = $v;
       
$i++;
    }
    return
$newarr;
}
/********************************/
?>

eg:

<?php
$foo_arr
[0] ='aa'
$foo_arr[1] ='bb'
$foo_arr[2] ='cc'
$foo_arr[3] ='bb'
$foo_arr[4] ='aa'
$foo_arr[5] ='dd'
?>

normal array_unique will return:

<?php
$foo_arr
[0] ='aa';
$foo_arr[1] ='bb';
$foo_arr[2] ='cc';
$foo_arr[3] ='';
$foo_arr[4] ='';
$foo_arr[5] ='dd'
?>

my_array_unique will return:

<?php
$foo_arr
[0] ='aa';
$foo_arr[1] ='bb';
$foo_arr[2] ='cc';
$foo_arr[3] ='dd'
?>
martin at lucas-smith dot co dot uk
27.01.2003 14:12
To get a list of the duplicated values in an array, array_unique isn't much help. Instead, use array_filter in conjunction with a callback function, as below:

<?php
$checkKeysUniqueComparison
= create_function('$value','if ($value > 1) return true;');
$result = array_keys (array_filter (array_count_values($array), $checkKeysUniqueComparison));
?>

These two lines therefore will create $result, an array of duplicated values in the array $array, once each. E.g. the array
$array = array ("a", "b", "a", "b", "x", "y", "z", "x");
gives the result
Array([0] => a [1] => b [2] => x)
juggler at webworkerinfo dot de
11.01.2003 2:20
in addition to bisqwit:
in some cases you can simply use serialize instead of recursivemakehash().

<?php
function array_unique2($input) {
   
$tmp = array();
    foreach(
$input as $a => $b)
       
$tmp[$a] = serialize($b);
   
$newinput = array();
    foreach(
array_unique($tmp) as $a => $b)
       
$newinput[$a] = $input[$a];
    return
$newinput;
}
?>

Have fun
Juggler
deigo at swirve dot NOSPAM dot com
23.09.2002 19:04
Before I found the mysql distinct I had to make a nicer array from the keys/values that I got from array_unique so.

<?php
$groups
=array_unique($groups);
$newgroup[0]=reset($groups);
for (
$x=1;$x<sizeof($groups);$x++)
{
 
$newgroup[$x]=next($groups);
}
?>
php at hp-site dot dk
29.08.2002 20:15
Try this:
array_flip(array_flip($array));

It gives the same result as the old array_unique()

29.08.2002 11:39
<?php
$truc
= array("l810u00","l810u00","l810q00");
$machin = array_unique($truc);
for(
$i=0;$i < count($machin) ; $i++){
print
$machin[$i]."
"
;
}
?>
result :
l810u00

This is not strange: $machin (as returned by array unique), contains "l810u00" either in key[0] or key[1] but not both (the key depends on the ersion of PHP), and "l810q00" in key[2].
The returned array has TWO elements so count($machin)==2.
The returned array has a hole in it, and you're not displaying its full content. You could verify it by using this display loop instead:
foreach($machine as $key=>$value){
print '[' . $key . '] => ' . $value . '
";
}
result:
[0] => l810q00
[2] => l810u00
(the first line may display [1] instead of [0] for PHP 4.0.1p3, but you'll get the same order of values and two lines, as expected). When calling array_values() on the result, you're building a new array with the same values in the same order, but with renumbered keys (without holes in numeric keys).
bisqwit at iki dot fi
24.05.2002 18:36
array_unique() doesn't return anything useful if your input is an
array containing arrays. This function overcomes the problem.
Any level of recursions is possible here. If the input is a plain
array, the result is compatible with array_unique() result.

<?php
function recursivemakehash($tab)
{
  if(!
is_array($tab))
    return
md5($tab);
 
$p = '';
  foreach(
$tab as $a => $b)
   
$p .= sprintf('%08X%08X', crc32($a), crc32(recursivemakehash($b)));
  return
$p;
}
function
array_unique2($input)
{
 
$dumdum = array();
  foreach(
$input as $a => $b)
   
$dumdum[$a] = recursivemakehash($b);
 
$newinput = array();
  foreach(
array_unique($dumdum) as $a => $b)
   
$newinput[$a] = $input[$a];
  return
$newinput;
}
?>
spunk at dasspunk dot NOSPAM dot com
14.11.2001 13:52
I needed a way of retaining the original array's keys in the new, unique array. I came up with this. It works for my purposes but may need refinement.

<?php
function my_array_unique($somearray)
{
   
asort($somearray);
   
reset($somearray);
   
$currentarrayvar = current($somearray);
    foreach (
$somearray as $key=>$var)
    {
        if (
next($somearray) != $currentarrayvar)
        {
           
$uniquearray[$key] = $currentarrayvar;
           
$currentarrayvar = current($somearray);
        }
    }
   
reset($uniquearray);
    return
$uniquearray;
}
?>
eltehaem at N dot O dot S dot P dot A dot M dot free dot poltronic dot net
11.08.2001 16:26
>array_unique() will keep the first key encountered
>for every value, and ignore all following keys.

This is true only in PHP 4.0.4pl1, i.e. the code below:

<?php
$temp
= Array ('pl', 'pl', 'en', 'en', 'cz', 'de', 'en', 'pl');
print_r($temp);
print_r(array_unique($temp));
?>

Will produce this output:

Array
(
    [0] => pl
    [1] => pl
    [2] => en
    [3] => en
    [4] => cz
    [5] => de
    [6] => en
    [7] => pl
)
Array
(
    [0] => pl
    [2] => en
    [4] => cz
    [5] => de
)

And in PHP 4.0.3pl1 will produce this output:

Array
(
    [0] => pl
    [1] => pl
    [2] => en
    [3] => en
    [4] => cz
    [5] => de
    [6] => en
    [7] => pl
)
Array
(
    [4] => cz
    [5] => de
    [6] => en
    [7] => pl
)

This little function resolves the problem:

<?php
function my_array_unique(&$old){
   
$new = array();
    foreach(
$old as $key => $value){
        if(!
in_array($value, $new)) $new[$key] = $value;
    }
    return
$new;
}
?>
az at top-webdesign dot de
10.07.2001 22:00
Attention!
If you use array_unique be aware of data-types! (I spent hours of debugging because of that ...).

For example, if you've got an array containing a '3' as number and another '3' as string it won't be eliminated by array_unique.

An Example where this can happen, without really thinking about it:

I've got an article-list with product-numbers where the third and fourth digit is the code for the producer. So I read in the file an process it line by line and put each producer-code into an array:
------------------------------
<?php
$i
=0;
while(
$line = fgets($csv, 10000) {
// splitting the line, product_no is the first part:

$data = explode(";", $line);

// putting the producer_code into an array:

$producer_id[$i] = trim(substr($data[0], 2, 2));

// make a special exception:

if(trim(substr($data[0], 2, 2)) == 40) {
$producer_id[$j] = '30';
}

// in the above line if you leave the 30 without the ''
// array_unique won't work!

$i++;
}

$producer_ids = array_values(array_unique($producer_id));
?>
-------------------------------
Result is to have all producer-ID's in an array without dupes.
rein at velt dot net
21.04.2001 21:44
Following code copies unique values from MyArray to TempArray.
Then copies non-empty elements from TempArray to UniqueArray.

Not the most elegant solution, but it works.

<?php
$TempArray
= array_unique($MyArray);
while (list(
$index,$data)=each($TempArray)) {
      if (
isempty($data)) {
         
$UniqueArray[$index]=$data;
      }
}
?>
jllamas at bal dot com dot mx
26.09.2000 6:25
It seems that array_unique creates an exact copy of the original array and then elimitates duplicate values. It does NOT change the "internal references" of the array. For example:

<?php
    $test_alfa
= array();
   
$test_alfa[0] = "aa";
   
$test_alfa[1] = "aa";
   
$test_alfa[2] = "aa";
   
$test_alfa[3] = "bb";
   
$test_alfa[4] = "aa";
   
$test_alfa[5] = "bb";
   
$test_alfa[6] = "cc";
   
$test_alfa[7] = "bb";
  
   
$test_beta= array_unique($test_alfa);
   
$numValues = count($test_beta);
    for (
$i = 0 ; $i <= 7 ; $i++)
       echo(
"test_beta[$i] = $test_beta[$i] <br>");
    echo (
"Number of elements in test_beta = $numValues ");
?>
will give you the following output:

test_beta[0] =
test_beta[1] = aa
test_beta[2] =
test_beta[3] =
test_beta[4] =
test_beta[5] = bb
test_beta[6] = cc
test_beta[7] =
Number of elements in test_beta = 3

The point is that you won't get the output you'd expect if you think that the values of the non duplicate elements are located in the first three array locations.

<?php
    $numValues
= count($test_beta);
    for (
$i=0;$i<=$numValues; $i++)
       echo(
"test_beta[$i] = $test_beta[$i] <br>");
    echo (
"Number of elements in test_beta = $numValues ");
?>

will give you:

test_beta[0] =
test_beta[1] = aa
test_beta[2] =
Number of elements in test_beta = 3

Hope that saves u some debugging time!
moose at ucdavis dot edu
15.08.2000 23:08
Here's a little function I wrote that's similar to array_unique, for PHP3 users.  It actually removes duplicated elements, but only works for 1 dimensional arrays.  It also doesn't return a value, it changes the input array:

<?php
function array_unique(&$thearray)
{
sort($thearray);
 
reset($thearray);

 
$newarray = array();
 
$i = 0;

 
$element = current($thearray);
 for (
$n=0;$n<sizeof($thearray);$n++)
 {if (
next($thearray) != $element)
  {
$newarray[$i] = $element;
  
$element = current($thearray);
  
$i++;
  }
 }
 
$thearray = $newarray;
}
?>



PHP Powered Diese Seite bei php.net
The PHP manual text and comments are covered by the Creative Commons Attribution 3.0 License © the PHP Documentation Group - Impressum - mail("TO:Reinhard Neidl",...)