Create multidimensional array unique for any single key index.
e.g I want to create multi dimentional unique array for specific code
Code :
My array is like this,
<?php
$details = array(
0 => array("id"=>"1", "name"=>"Mike", "num"=>"9876543210"),
1 => array("id"=>"2", "name"=>"Carissa", "num"=>"08548596258"),
2 => array("id"=>"1", "name"=>"Mathew", "num"=>"784581254"),
);
?>
You can make it unique for any field like id, name or num.
I have develop this function for same :
<?php
function unique_multidim_array($array, $key) {
$temp_array = array();
$i = 0;
$key_array = array();
foreach($array as $val) {
if (!in_array($val[$key], $key_array)) {
$key_array[$i] = $val[$key];
$temp_array[$i] = $val;
}
$i++;
}
return $temp_array;
}
?>
Now, call this function anywhere from your code,
something like this,
<?php
$details = unique_multidim_array($details,'id');
?>
Output will be like this :
<?php
$details = array(
0 => array("id"=>"1","name"=>"Mike","num"=>"9876543210"),
1 => array("id"=>"2","name"=>"Carissa","num"=>"08548596258"),
);
?>
array_unique
(PHP 4 >= 4.0.1, PHP 5, PHP 7)
array_unique — Removes duplicate values from an array
Description
array_unique
( array
$array
[, int $sort_flags = SORT_STRING
] ) : array
Takes an input array and returns a new array
without duplicate values.
Note that keys are preserved. If multiple elements compare equal under
the given sort_flags, then the key and value of
the first equal element will be retained.
Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used.
Parameters
-
array -
The input array.
-
sort_flags -
The optional second parameter
sort_flagsmay be used to modify the sorting behavior using these values:Sorting type flags:
-
SORT_REGULAR- compare items normally (don't change types) -
SORT_NUMERIC- compare items numerically -
SORT_STRING- compare items as strings -
SORT_LOCALE_STRING- compare items as strings, based on the current locale.
-
Return Values
Returns the filtered array.
Changelog
| Version | Description |
|---|---|
| 7.2.0 |
If sort_flags is SORT_STRING,
formerly array has been copied and non-unique
elements have been removed (without packing the array afterwards), but
now a new array is built by adding the unique elements. This can result
in different numeric indexes.
|
| 5.2.10 |
Changed the default value of sort_flags back to
SORT_STRING.
|
| 5.2.9 |
Added the optional sort_flags defaulting
to SORT_REGULAR. Prior to 5.2.9, this function used to sort
the array with SORT_STRING internally.
|
Examples
Example #1 array_unique() example
<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input);
print_r($result);
?>
The above example will output:
Array
(
[a] => green
[0] => red
[1] => blue
)
Example #2 array_unique() and types
<?php
$input = array(4, "4", "3", 4, 3, "3");
$result = array_unique($input);
var_dump($result);
?>
The above example will output:
array(2) {
[0] => int(4)
[2] => string(1) "3"
}
Notes
Note: Note that array_unique() is not intended to work on multi dimensional arrays.
add a note
User Contributed Notes 49 notes
Ghanshyam Katriya(anshkatriya at gmail) ¶
4 years ago
stoff@ ¶
2 years ago
In reply to performance tests array_unique vs foreach.
In PHP7 there were significant changes to Packed and Immutable arrays resulting in the performance difference to drop considerably. Here is the same test on php7.1 here;
http://sandbox.onlinephpfunctions.com/code/2a9e986690ef8505490489581c1c0e70f20d26d1
$max = 770000; //large enough number within memory allocation
$arr = range(1,$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 513333 in 1.0876770019531
$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 513333 in 0.054931879043579
Anonymous ¶
9 years ago
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
?>
Ome_Henk ¶
12 years ago
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.
Ray dot Paseur at SometimesUsesGmail dot com ¶
11 years ago
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($common_stuff);
?>
regeda at inbox dot ru ¶
9 years ago
recursive array unique for multiarrays
<?php
function super_unique($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 $result;
}
?>
mnbayazit ¶
11 years ago
Case insensitive; will keep first encountered value.
<?php
function array_iunique($array) {
$lowered = array_map('strtolower', $array);
return array_intersect_key($array, array_unique($lowered));
}
?>
tim at heuer dot nz ¶
3 years ago
I created a function for doing array_unique with a custom in_array function. So, if elements are considered in the array passed to this function, the array returned won't include elements that are considered equal and only return the values from the first array that are not considered in the array:
<?php
function uniqueBy(array $array, callable $in_array_func) {
$result = array();
foreach ($array as $key => $item) {
if (!$in_array_func($item, $result)) {
$result[$key] = $item;
}
}
return $result;
}
?>
Example usage:
<?php
$in_array_func = function($item, $array) {
$fromBower = function($item) {
$result = substr($item, strpos($item, 'bower_components'));
return $result;
};
foreach ($array as $myItem) {
if ($fromBower($item) == $fromBower($myItem)) {
return true;
}
}
return false;
};
// ...
$jss = uniqueBy($jss, $in_array_func);
?>
mostafatalebi at rocketmail dot com ¶
5 years ago
If you find the need to get a sorted array without it preserving the keys, use this code which has worked for me:
<?php
$array = array("hello", "fine", "good", "fine", "hello", "bye");
$get_sorted_unique_array = array_values(array_unique($array));
?>
The above code returns an array which is both unique and sorted from zero.
keneks at gmail dot com ¶
13 years ago
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_has_duplicates(array $array)
{
$uniq = array_unique($array);
return count($uniq) != count($array);
}
?>
agarcia at rsn dot com dot co ¶
13 years ago
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 $entrega;
}
?>
csaba at alum dot mit dot edu ¶
15 years ago
The following is an efficient, adaptable implementation of array_unique which always retains the first key having a given value:
<?php
function array_unique2(&$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
quecoder at gmail ¶
11 years ago
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 )
zoolyka at gmail dot com ¶
3 years ago
I found the simplest way to "unique" multidimensional arrays as follows:
<?php
$array = array(
'a' => array(1, 2),
'b' => array(1, 2),
'c' => array(2, 2),
'd' => array(2, 1),
'e' => array(1, 1),
);
$array = array_map('json_encode', $array);
$array = array_unique($array);
$array = array_map('json_decode', $array);
print_r($array);
?>
As you can see "b" will be removed without any errors or notices.
sashasimkin at gmail dot com ¶
7 years ago
My object unique function:
<?php
function object_unique( $obj ){
$objArray = (array) $obj;
$objArray = array_intersect_assoc( array_unique( $objArray ), $objArray );
foreach( $obj as $n => $f ) {
if( !array_key_exists( $n, $objArray ) ) unset( $obj->$n );
}
return $obj;
}
?>
And these code:
<?php
class Test{
public $pr0 = 'string';
public $pr1 = 'string1';
public $pr2 = 'string';
public $pr3 = 'string2';
}
$obj = new Test;
var_dump( object_unique( $obj ) );
?>
returns:
object(Test)[1]
public 'pr0' => string 'string' (length=6)
public 'pr1' => string 'string1' (length=7)
public 'pr3' => string 'string2' (length=7)
jusvalceanu - SPAM at SPAM - yahoo dot com ¶
10 years ago
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); // $new is our sorted array
?>
Have fun tweaking this ;)) i know you will ;))
From Romania With Love
dirk dot avery a t gmail ¶
10 years ago
Although array_unique is not intended to work with multi-dimensional arrays, it does on 5.2.9. However, it does not for 5.2.5. Beware.
Ludovico Grossi ¶
4 years ago
[Editor's note: please note that this will not work well with non-scalar values in the array. Array keys can not be arrays themselves, nor streams, resources, etc. Flipping the array causes a change in key-name]
You can do a super fast version of array_unique directly in PHP, even faster than the other solution posted in the comments!
Compared to the built in function it is 20x faster! (2x faster than the solution in the comments).
<?php
function superfast_array_unique($array) {
return array_keys(array_flip($array));
}
?>
This works faster for small and big arrays.
bx16soupapes at gmail dot com ¶
6 years ago
Another form to make an array unique (manual):
This is my array
Array
(
[0] => Array
(
[0] => 40665
[1] => 40665
[2] => 40665
[3] => 40665
[4] => 40666
[5] => 40666
[6] => 40666
[7] => 40666
[8] => 40667
[9] => 40667
[10] => 40667
[11] => 40667
[12] => 40667
[13] => 40668
[14] => 40668
[15] => 40668
[16] => 40668
[17] => 40668
[18] => 40669
[19] => 40669
[20] => 40670
[21] => 40670
[22] => 40670
[23] => 40670
[24] => 40671
[25] => 40671
[26] => 40671
[27] => 40671
[28] => 40671
)
[1] => Array
(
[0] => 40672
[1] => 40672
[2] => 40672
[3] => 40672
)
)
this is my script:
$anterior = 0;
foreach($item as $array_key => $array_value)
{
echo "<li>$array_key";
echo "<ul>";
foreach($array_value as $xarray_key => $xarray_value){
if($xarray_value != $anterior) {
echo "<li>$xarray_key => $xarray_value";
$item_nuevo[$array_key][] = $xarray_value; // or to use the same key number $item_nuevo[$array_key][$xarray_key] = $xarray_value;
}
$anterior = $xarray_value;
}
echo "</ul>";
}
result:
0
0 => 40665
4 => 40666
8 => 40667
13 => 40668
18 => 40669
20 => 40670
24 => 40671
1
0 => 40672
saludos desde chile.
amri [ at t] dhstudio dot eu ¶
9 years ago
I searched how to show only the de-duplicate elements from array, but failed.
Here is my solution:
<?php
function arrayUniqueElements($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');
$result=arrayUniqueElements($arr1);
print_r($result);exit;
?>
Output:
Array
(
[4] => xyzzy
[12] => |
[16] => &
[21] => foobar
)
webmaster at jukkis dot net ¶
12 years ago
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, 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.
falundir at gmail dot com ¶
1 year ago
I find it odd that there is no version of this function which allows you to use a comparator callable in order to determine items equality (like array_udiff and array_uintersect). So, here's my version for you:
<?php
function array_uunique(array $array, callable $comparator): array {
$unique_array = [];
do {
$element = array_shift($array);
$unique_array[] = $element;
$array = array_udiff(
$array,
[$element],
$comparator
);
} while (count($array) > 0);
return $unique_array;
}
?>
And here is a test code:
<?php
class Foo {
public $a;
public function __construct(int $a) {
$this->a = $a;
}
}
$array_of_objects = [new Foo(2), new Foo(1), new Foo(3), new Foo(2), new Foo(2), new Foo(1)];
$comparator = function (Foo $foo1, Foo $foo2): int {
return $foo1->a <=> $foo2->a;
};
var_dump(array_uunique($array_of_objects, $comparator)); // should output [Foo(2), Foo(1), Foo(3)]
?>
subhrajyoti dot de007 at gmail dot com ¶
1 year ago
Simple and clean way to get duplicate entries removed from a multidimensional array.
<?php
$multi_array = $multi_array [0];
$multi_array = array_unique($multi_array);
print_r($multi_array);
?>
Fabiano ¶
1 year ago
As for PHP 7.1.12, this is the comparison between array_keys(array_flip()), array_flip(array_flip()), for each elimination and array_unique. The array_keys(array_flip()) is the fastest method to remove duplication values from a single dimension array:
<?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);
$time += microtime(true);
echo "<br>deduped to ".count($res1)." in ".$time;
// deduped to 666667 in 0.78185796737671
// memory used: 33558528
$time = -microtime(true);
$res2 = array_flip(array_flip($arr));
$time += microtime(true);
echo "<br><br>deduped to ".count($res2)." in ".$time;
// deduped to 666667 in 0.072191953659058
// memory used: 3774873
$time = -microtime(true);
$res3 = array();
foreach($arr as $key=>$val) {
$res3[$val] = true;
}
$res3 = array_keys($res3);
$time += microtime(true);
echo "<br /><br>deduped to ".count($res3)." in ".$time;
// deduped to 666667 in 0.095494985580444
// memory used: 33558528
$time = -microtime(true);
$res4 = array_keys(array_flip($arr));
$time += microtime(true);
echo "<br /><br>deduped to ".count($res4)." in ".$time;
// deduped to 666667 in 0.05807900428772
// memory used: 33558528
calexandrepcjr at gmail dot com ¶
2 years ago
Following the Ghanshyam Katriya idea, but with an array of objects, where the $key is related to object propriety that you want to filter the uniqueness of array:
<?php
function obj_multi_unique($obj, $key = false)
{
$totalObjs = count($obj);
if (is_array($obj) && $totalObjs > 0 && is_object($obj[0]) && ($key && !is_numeric($key))) {
for ($i = 0; $i < $totalObjs; $i++) {
if (isset($obj[$i])) {
for ($j = $i + 1; $j < $totalObjs; $j++) {
if (isset($obj[$j]) && $obj[$i]->{$key} === $obj[$j]->{$key}) {
unset($obj[$j]);
}
}
}
}
return array_values($obj);
} else {
throw new Exception('Invalid argument or your array of objects is empty');
}
}
?>
Matt S ¶
1 year ago
In case you are looking for a function that works like array_unique but does not do the string conversion first.
<?php
function array_unique_full($arr, $strict = false) {
return array_filter($arr, function($v, $k) use ($arr, $strict) {
return array_search($v, $arr, $strict) === $k;
}, ARRAY_FILTER_USE_BOTH);
}
?>
gma (at) qoob (dot) gr ¶
7 years ago
Lets say that you want to capture unique values from multidimensional arrays and flatten them in 0 depth.
i.e.
<?php
$tmp = array( 'a' => array( 1,2,3,4 ), 'b' => array( 'c' => array( 4,5,6,7 ) ) );
?>
will return with array_flat( $tmp ) --> array( 1,2,3,4,5,6,7 );
I hope that the function will help someone
<?php
/**
* @params : $a array the recursion array
* : $s array storage array
* : $l integer the depth level
*
*/
if( !function_exists( 'array_flat' ) )
{
function array_flat( $a, $s = array( ), $l = 0 )
{
# check if this is an array
if( !is_array( $a ) ) return $s;
# go through the array values
foreach( $a as $k => $v )
{
# check if the contained values are arrays
if( !is_array( $v ) )
{
# store the value
$s[ ] = $v;
# move to the next node
continue;
}
# increment depth level
$l++;
# replace the content of stored values
$s = array_flat( $v, $s, $l );
# decrement depth level
$l--;
}
# get only unique values
if( $l == 0 ) $s = array_values( array_unique( $s ) );
# return stored values
return $s;
} # end of function array_flat( ...
}
?>
Friendly Code ¶
8 years ago
I required a function that removed a specific duplicate entry from an array and ignoring all others so came up with this:
<?php
function specified_array_unique($array, $value)
{
$count = 0;
foreach($array as $array_key => $array_value)
{
if ( ($count > 0) && ($array_value == $value) )
{
unset($array[$array_key]);
}
if ($array_value == $value) $count++;
}
return array_filter($array);
}
?>
0cool.f ¶
8 years ago
Hope this can help...
<?php
function array_unique_key_group($array) {
if(!is_array($array))
return false;
$temp = array_unique($array);
foreach($array as $key => $val) {
$i = array_search($val,$temp);
if(!empty($i) && $key != $i) {
$temp[$i.','.$key] = $temp[$i];
unset($temp[$i]);
}
}
return $temp;
}
?>
this function return an array that is unique, but preserve every key for the element...
sorry for bad english I'm italian...
$array['asd'] = 'value';
$array['lol'] = 'value';
$array['foo'] = 'val';
$array['bar'] = 'val';
var_dump(array_unique_key_group($array));
// will be output
array(2) { ["asd,lol"]=> string(5) "value" ["foo,bar"]=> string(3) "val" }
brendel at krumedia dot de ¶
9 years ago
Prior to 5.2.9 you may create a list of unique objects this way:
<?php
for (; ; ) {
// ...
$uniqueObjectList[spl_object_hash($myObject)] = $myObject;
}
?>
serg dot podtynnyi at gmail dot com ¶
10 years ago
//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,$data2))));
?>
PHP Expert ¶
11 years ago
Case insensitive for PHP v4.x and up.
<?php
function in_iarray($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($result);
/*
Array
(
[0] => aAa
[1] => bBb
[2] => cCc
[9] => XXX
)
*/
?>
Dorphalsig ¶
11 years ago
I had a problem with array_unique and multidimensional arrays ... Maybe there's a better way to do this, but this will work for any dimensional arrays.
<?php
function arrayUnique($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;
}
?>
geuis dot teses at gmail dot com ¶
12 years ago
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));
?>
uditsawhney at yahoo dot com ¶
13 years ago
<?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));
?>
mcmeijer at yahoo dot com ¶
13 years ago
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 ¶
13 years ago
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($problem));
?>
arr1 ¶
12 years ago
Just to note that array_unique, treats null values as none unique values. So if your using array_unique to detect duplicate values it will also detect multiple null values.
muddmonkey@harveyMcoldotedu ¶
14 years ago
If you're doing numeric arrays etc. I found flip-flip to work much better than array_unique:
<?PHP
function microtime_float(){ //timing
list($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'.$i%13;)
gives:
0.42909598350525 (using unique)
0.023258924484253 (using flip-flip)
Which is not AS great, but still 20x faster than unique.
In both cases the flip-flip seems to use less memory than the unique.
Granted the flip-flip doesn't work for all cases, but if you're doing simple stuff like this, the flip-flip will give you better run times.
~JF
spunk at dasspunk dot NOSPAM dot com ¶
17 years ago
I needed a way of retaining the original array's keys in the new, unique array. I came up with this. It works for my purposes but may need refinement.
<?php
function my_array_unique($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 $uniquearray;
}
?>
patrikG at home dot net ¶
15 years ago
If you need to have the keys of the duplicates in an array returned, you may find this function useful:
<?php
function unique_events($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
)
)
az at top-webdesign dot de ¶
18 years ago
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.
yosef_cool_ha at hotmail dot com ¶
6 years ago
if you wish to unique the arrays recusively(multi dimensional) no matter how deep hope this function can help you:
function array_unique_recusive($arr){
foreach($arr as $key=>$value)
if(gettype($value)=='array')
$arr[$key]=array_unique_recusive($value);
return array_unique($arr,SORT_REGULAR);
}
michiel ed thalent nl ¶
9 years ago
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.
martin at lucas-smith dot co dot uk ¶
16 years ago
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)
Anonymous ¶
17 years ago
<?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).
CertaiN ¶
5 years ago
Let's implement array_unique_callback() !
Function:
<?php
function array_unique_callback(array $arr, callable $callback, $strict = false) {
return array_filter(
$arr,
function ($item) use ($strict, $callback) {
static $haystack = array();
$needle = $callback($item);
if (in_array($needle, $haystack, $strict)) {
return false;
} else {
$haystack[] = $needle;
return true;
}
}
);
}
?>
Usage:
<?php
$companies = array(
0 => array(
'name' => 'Foo - Ltd.',
'phone' => 'XXX-YYY-ZZZ',
'category' => 'supplyment',
),
1 => array(
'name' => 'Bar - Ltd.',
'phone' => 'xxx-yyy-zzz',
'category' => 'supplyment',
),
2 => array(
'name' => 'Baz - Ltd.',
'phone' => 'AAA-BBB-CCC',
'category' => 'alcohol',
),
);
$companies = array_unique_callback(
$companies,
function ($company) {
return $company['category'];
}
);
print_r($companies);
?>
Result:
Array
(
[0] => Array
(
[name] => Foo - Ltd.
[phone] => XXX-YYY-ZZZ
[category] => supplyment
)
[2] => Array
(
[name] => Baz - Ltd.
[phone] => AAA-BBB-CCC
[category] => alcohol
)
)
Tim S. ¶
6 years ago
I had to write a bunch of results to an array with a high probability of duplicates.
The array was written to the file in chunks, using a for loop. It occurred to me that I often had blank lines in my file.
Because this function preserve keys, I had gaps in my numeric keys. If you don't want to preserve keys, like me, you can use the following function.
<?php
function array_unique_ignore_keys(&$array, $sort_flags = SORT_STRING) {
return array_values(array_unique($array, $sort_flags));
}
?>
MoD ¶
13 years ago
The shortest way i found to remove duplicate array from a column,
For example if you parse Multiple XML sources, you can remove duplicate items that contain the same link.
<?PHP
function remove_duplicate($array, $field)
{
foreach ($array as $sub)
$cmp[] = $sub[$field];
$unique = array_unique($cmp);
foreach ($unique as $k => $rien)
$new[] = $array[$k];
return $new;
}
?>
