Related
How can I remove duplicate values from a multi-dimensional array in PHP?
Example array:
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
[3] => Array
(
[0] => abc
[1] => def
)
[4] => Array
(
[0] => ghi
[1] => jkl
)
[5] => Array
(
[0] => mno
[1] => pql
)
)
Here is another way. No intermediate variables are saved.
We used this to de-duplicate results from a variety of overlapping queries.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Since 5.2.9 you can use array_unique() if you use the SORT_REGULAR flag like so:
array_unique($array, SORT_REGULAR);
This makes the function compare elements for equality as if $a == $b were being used, which is perfect for your case.
Output
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
)
Keep in mind, though, that the documentation states:
array_unique() is not intended to work on multi dimensional arrays.
I had a similar problem but I found a 100% working solution for it.
<?php
function super_unique($array,$key)
{
$temp_array = [];
foreach ($array as &$v) {
if (!isset($temp_array[$v[$key]]))
$temp_array[$v[$key]] =& $v;
}
$array = array_values($temp_array);
return $array;
}
$arr="";
$arr[0]['id']=0;
$arr[0]['titel']="ABC";
$arr[1]['id']=1;
$arr[1]['titel']="DEF";
$arr[2]['id']=2;
$arr[2]['titel']="ABC";
$arr[3]['id']=3;
$arr[3]['titel']="XYZ";
echo "<pre>";
print_r($arr);
echo "unique*********************<br/>";
print_r(super_unique($arr,'titel'));
?>
Another way. Will preserve keys as well.
function array_unique_multidimensional($input)
{
$serialized = array_map('serialize', $input);
$unique = array_unique($serialized);
return array_intersect_key($input, $unique);
}
Array
(
[0] => Array
(
[id] => 1
[name] => john
)
[1] => Array
(
[id] => 2
[name] => smith
)
[2] => Array
(
[id] => 3
[name] => john
)
[3] => Array
(
[id] => 4
[name] => robert
)
)
$temp = array_unique(array_column($array, 'name'));
$unique_arr = array_intersect_key($array, $temp);
This will remove the duplicate names from array. unique by key
If "remove duplicates" means "remove duplicates, but let one there", a solution might be to apply the array_unique(...) on the "identifier column" first and then to remove in the original array all the keys, that have been removed from the column array:
$array = [
[
'id' => '123',
'foo' => 'aaa',
'bar' => 'bbb'
],
[
'id' => '123',
'foo' => 'ccc',
'bar' => 'ddd'
],
[
'id' => '567',
'foo' => 'eee',
'bar' => 'fff'
]
];
$ids = array_column($array, 'id');
$ids = array_unique($ids);
$array = array_filter($array, function ($key, $value) use ($ids) {
return in_array($value, array_keys($ids));
}, ARRAY_FILTER_USE_BOTH);
The result is:
Array
(
[0] => Array
(
[id] => 123
[foo] => aaa
[bar] => bbb
)
[2] => Array
(
[id] => 567
[foo] => eee
[bar] => fff
)
)
The user comments on the array_unique() documentation have many solutions to this. Here is one of them:
kenrbnsn at rbnsn dot com
27-Sep-2005 12:09
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.
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);
}
This is from http://ca3.php.net/manual/en/function.array-unique.php#57202.
if you need to eliminate duplicates on specific keys, such as a mysqli id, here's a simple funciton
function search_array_compact($data,$key){
$compact = [];
foreach($data as $row){
if(!in_array($row[$key],$compact)){
$compact[] = $row;
}
}
return $compact;
}
Bonus Points
You can pass an array of keys and add an outer foreach, but it will be 2x slower per additional key.
if you have an array like this:
(users is the name of the array)
Array=>
[0] => (array)
'user' => 'john'
'age' => '23'
[1] => (array)
'user' => 'jane'
'age' => '20'
[2]=> (array)
'user' => 'john'
'age' => '23'
and you want to delete duplicates...then:
$serialized = array();
for ($i=0; $i < sizeof($users); $i++) {
$test = in_array($users['user'], $serialized);
if ($test == false) {
$serialized[] = $users['user'];
}
}
can be a solution :P
Lots of person asked me how to make Unique multidimensional array. I have taken reference from your comment and it helps me.
First of All, Thanks to #jeromegamez #daveilers for your solution. But every time i gave the answer, they asked me how this 'serialize' and 'unserialize' works. That's why i want to share the reason of this with you so that it will help more people to understand the concept behind this.
I am explaining why we use 'serialize' and 'unserialize' in steps :
Step 1: Convert the multidimensional array to one-dimensional array
To convert the multidimensional array to a one-dimensional array, first generate byte stream representation of all the elements (including nested arrays) inside the array. serialize() function can generate byte stream representation of a value. To generate byte stream representation of all the elements, call serialize() function inside array_map() function as a callback function. The result will be a one dimensional array no matter how many levels the multidimensional array has.
Step 2: Make the values unique
To make this one dimensional array unique, use array_unique() function.
Step 3: Revert it to the multidimensional array
Though the array is now unique, the values looks like byte stream representation. To revert it back to the multidimensional array, use unserialize() function.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Thanks again for all this.
A very easy and logical way to Unique a multi dimension array is as follows,
If you have array like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value1
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value4
)
)
use foreach to solve this:
foreach($array as $k=>$v){
$unique=array_unique($v);
$array[$k]=$unique;
}
it will give you following result:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
[4] => Value4
)
)
and if you want to rearrange the order of the keys,
foreach($array as $k=>$v){
$unique= array_values(array_unique($v));
$array[$k]=$unique;
}
This operation will give you arranged key values like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
[3] => Value4
)
)
I hope this will clear everything.
An easy to read solution, probably not the most efficient:
function arrayUnique($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;
}
As people are saying array_unique() is very slow, here is a snippet I use for one level multidimensional array.
$serialized_array = array_map("serialize", $input);
foreach ($serialized_array as $key => $val) {
$result[$val] = true;
}
$output = array_map("unserialize", (array_keys($result)));
Reference first user contributed note of array_unique() function page in php.net
This solution is relevant only when uniqueness is needed for one array column, for example here if we need the uniqueness in index #0 of the arrays.
Solution #1:
Using array_filter with an anonymous function and a static variable:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$list = array_filter($list, function ($item) {
static $values = [];
if (!in_array($item[0], $values)) {
$values[] = $item[0];
return true;
} else {
return false;
}
});
var_dump($list);
Solution #2:
Since the value when we want the uniqueness are of string type, we can remap the original global array to use these values as keys, which will remove duplicates as we remap it:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$unique = [];
foreach ($list as $item) {
$unique[$item[0]] = $item;
}
// Remap again to integers
$unique = array_values($unique);
var_dump($unique);
An alternative to serialize and unique
$test = [
['abc','def'],
['ghi','jkl'],
['mno','pql'],
['abc','def'],
['ghi','jkl'],
['mno','pql'],
];
$result = array_reduce(
$test,
function($carry,$item){
if(!in_array($item,$carry)) {
array_push($carry,$item);
}
return $carry;
},
[]
);
var_dump($result);
/*
php unique.php
array(3) {
[0] =>
array(2) {
[0] =>
string(3) "abc"
[1] =>
string(3) "def"
}
[1] =>
array(2) {
[0] =>
string(3) "ghi"
[1] =>
string(3) "jkl"
}
[2] =>
array(2) {
[0] =>
string(3) "mno"
[1] =>
string(3) "pql"
}
}
*/
I've given this problem a lot of thought and have determined that the optimal solution should follow two rules.
For scalability, modify the array in place; no copying to a new array
For performance, each comparison should be made only once
With that in mind and given all of PHP's quirks, below is the solution I came up with. Unlike some of the other answers, it has the ability to remove elements based on whatever key(s) you want. The input array is expected to be numeric keys.
$count_array = count($input);
for ($i = 0; $i < $count_array; $i++) {
if (isset($input[$i])) {
for ($j = $i+1; $j < $count_array; $j++) {
if (isset($input[$j])) {
//this is where you do your comparison for dupes
if ($input[$i]['checksum'] == $input[$j]['checksum']) {
unset($input[$j]);
}
}
}
}
}
The only drawback is that the keys are not in order when the iteration completes. This isn't a problem if you're subsequently using only foreach loops, but if you need to use a for loop, you can put $input = array_values($input); after the above to renumber the keys.
try this solution for (n) Dimensional array with non-restricted length
for example this array
$arr= [
0 => [0=>"a" , 1=>"b" , 2=>"c" ] ,
1 => [0=>"x" , 1=>"b" , 2=>"a", 3=>"p"],
2=> [
[
0=>"y" ,
1=>"b" ,
2=> [0=>"x" , 1=>"m" , 2=>"a"]
],
1=>"z" ,
2=>"v"
]
];
This would be the solution
$ar2=[];
$ar3=[];
function test($arr){
global $ar2,$ar3;
if(is_array($arr)){
return array_map("test",$arr);
}
if(!isset($ar2[$arr])){
$ar2[$arr]=1;
$ar3[]=$arr;
}
}
array_map("test",$arr);
print_r($ar3);
Based on the Answer marked as correct, adding my answer. Small code added just to reset the indices-
$input = array_values(array_map("unserialize", array_unique(array_map("serialize", $inputArray))));
How can I remove duplicate values from a multi-dimensional array in PHP?
Example array:
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
[3] => Array
(
[0] => abc
[1] => def
)
[4] => Array
(
[0] => ghi
[1] => jkl
)
[5] => Array
(
[0] => mno
[1] => pql
)
)
Here is another way. No intermediate variables are saved.
We used this to de-duplicate results from a variety of overlapping queries.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Since 5.2.9 you can use array_unique() if you use the SORT_REGULAR flag like so:
array_unique($array, SORT_REGULAR);
This makes the function compare elements for equality as if $a == $b were being used, which is perfect for your case.
Output
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
)
Keep in mind, though, that the documentation states:
array_unique() is not intended to work on multi dimensional arrays.
I had a similar problem but I found a 100% working solution for it.
<?php
function super_unique($array,$key)
{
$temp_array = [];
foreach ($array as &$v) {
if (!isset($temp_array[$v[$key]]))
$temp_array[$v[$key]] =& $v;
}
$array = array_values($temp_array);
return $array;
}
$arr="";
$arr[0]['id']=0;
$arr[0]['titel']="ABC";
$arr[1]['id']=1;
$arr[1]['titel']="DEF";
$arr[2]['id']=2;
$arr[2]['titel']="ABC";
$arr[3]['id']=3;
$arr[3]['titel']="XYZ";
echo "<pre>";
print_r($arr);
echo "unique*********************<br/>";
print_r(super_unique($arr,'titel'));
?>
Another way. Will preserve keys as well.
function array_unique_multidimensional($input)
{
$serialized = array_map('serialize', $input);
$unique = array_unique($serialized);
return array_intersect_key($input, $unique);
}
Array
(
[0] => Array
(
[id] => 1
[name] => john
)
[1] => Array
(
[id] => 2
[name] => smith
)
[2] => Array
(
[id] => 3
[name] => john
)
[3] => Array
(
[id] => 4
[name] => robert
)
)
$temp = array_unique(array_column($array, 'name'));
$unique_arr = array_intersect_key($array, $temp);
This will remove the duplicate names from array. unique by key
If "remove duplicates" means "remove duplicates, but let one there", a solution might be to apply the array_unique(...) on the "identifier column" first and then to remove in the original array all the keys, that have been removed from the column array:
$array = [
[
'id' => '123',
'foo' => 'aaa',
'bar' => 'bbb'
],
[
'id' => '123',
'foo' => 'ccc',
'bar' => 'ddd'
],
[
'id' => '567',
'foo' => 'eee',
'bar' => 'fff'
]
];
$ids = array_column($array, 'id');
$ids = array_unique($ids);
$array = array_filter($array, function ($key, $value) use ($ids) {
return in_array($value, array_keys($ids));
}, ARRAY_FILTER_USE_BOTH);
The result is:
Array
(
[0] => Array
(
[id] => 123
[foo] => aaa
[bar] => bbb
)
[2] => Array
(
[id] => 567
[foo] => eee
[bar] => fff
)
)
The user comments on the array_unique() documentation have many solutions to this. Here is one of them:
kenrbnsn at rbnsn dot com
27-Sep-2005 12:09
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.
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);
}
This is from http://ca3.php.net/manual/en/function.array-unique.php#57202.
if you need to eliminate duplicates on specific keys, such as a mysqli id, here's a simple funciton
function search_array_compact($data,$key){
$compact = [];
foreach($data as $row){
if(!in_array($row[$key],$compact)){
$compact[] = $row;
}
}
return $compact;
}
Bonus Points
You can pass an array of keys and add an outer foreach, but it will be 2x slower per additional key.
if you have an array like this:
(users is the name of the array)
Array=>
[0] => (array)
'user' => 'john'
'age' => '23'
[1] => (array)
'user' => 'jane'
'age' => '20'
[2]=> (array)
'user' => 'john'
'age' => '23'
and you want to delete duplicates...then:
$serialized = array();
for ($i=0; $i < sizeof($users); $i++) {
$test = in_array($users['user'], $serialized);
if ($test == false) {
$serialized[] = $users['user'];
}
}
can be a solution :P
Lots of person asked me how to make Unique multidimensional array. I have taken reference from your comment and it helps me.
First of All, Thanks to #jeromegamez #daveilers for your solution. But every time i gave the answer, they asked me how this 'serialize' and 'unserialize' works. That's why i want to share the reason of this with you so that it will help more people to understand the concept behind this.
I am explaining why we use 'serialize' and 'unserialize' in steps :
Step 1: Convert the multidimensional array to one-dimensional array
To convert the multidimensional array to a one-dimensional array, first generate byte stream representation of all the elements (including nested arrays) inside the array. serialize() function can generate byte stream representation of a value. To generate byte stream representation of all the elements, call serialize() function inside array_map() function as a callback function. The result will be a one dimensional array no matter how many levels the multidimensional array has.
Step 2: Make the values unique
To make this one dimensional array unique, use array_unique() function.
Step 3: Revert it to the multidimensional array
Though the array is now unique, the values looks like byte stream representation. To revert it back to the multidimensional array, use unserialize() function.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Thanks again for all this.
A very easy and logical way to Unique a multi dimension array is as follows,
If you have array like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value1
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value4
)
)
use foreach to solve this:
foreach($array as $k=>$v){
$unique=array_unique($v);
$array[$k]=$unique;
}
it will give you following result:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
[4] => Value4
)
)
and if you want to rearrange the order of the keys,
foreach($array as $k=>$v){
$unique= array_values(array_unique($v));
$array[$k]=$unique;
}
This operation will give you arranged key values like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
[3] => Value4
)
)
I hope this will clear everything.
An easy to read solution, probably not the most efficient:
function arrayUnique($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;
}
As people are saying array_unique() is very slow, here is a snippet I use for one level multidimensional array.
$serialized_array = array_map("serialize", $input);
foreach ($serialized_array as $key => $val) {
$result[$val] = true;
}
$output = array_map("unserialize", (array_keys($result)));
Reference first user contributed note of array_unique() function page in php.net
This solution is relevant only when uniqueness is needed for one array column, for example here if we need the uniqueness in index #0 of the arrays.
Solution #1:
Using array_filter with an anonymous function and a static variable:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$list = array_filter($list, function ($item) {
static $values = [];
if (!in_array($item[0], $values)) {
$values[] = $item[0];
return true;
} else {
return false;
}
});
var_dump($list);
Solution #2:
Since the value when we want the uniqueness are of string type, we can remap the original global array to use these values as keys, which will remove duplicates as we remap it:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$unique = [];
foreach ($list as $item) {
$unique[$item[0]] = $item;
}
// Remap again to integers
$unique = array_values($unique);
var_dump($unique);
An alternative to serialize and unique
$test = [
['abc','def'],
['ghi','jkl'],
['mno','pql'],
['abc','def'],
['ghi','jkl'],
['mno','pql'],
];
$result = array_reduce(
$test,
function($carry,$item){
if(!in_array($item,$carry)) {
array_push($carry,$item);
}
return $carry;
},
[]
);
var_dump($result);
/*
php unique.php
array(3) {
[0] =>
array(2) {
[0] =>
string(3) "abc"
[1] =>
string(3) "def"
}
[1] =>
array(2) {
[0] =>
string(3) "ghi"
[1] =>
string(3) "jkl"
}
[2] =>
array(2) {
[0] =>
string(3) "mno"
[1] =>
string(3) "pql"
}
}
*/
I've given this problem a lot of thought and have determined that the optimal solution should follow two rules.
For scalability, modify the array in place; no copying to a new array
For performance, each comparison should be made only once
With that in mind and given all of PHP's quirks, below is the solution I came up with. Unlike some of the other answers, it has the ability to remove elements based on whatever key(s) you want. The input array is expected to be numeric keys.
$count_array = count($input);
for ($i = 0; $i < $count_array; $i++) {
if (isset($input[$i])) {
for ($j = $i+1; $j < $count_array; $j++) {
if (isset($input[$j])) {
//this is where you do your comparison for dupes
if ($input[$i]['checksum'] == $input[$j]['checksum']) {
unset($input[$j]);
}
}
}
}
}
The only drawback is that the keys are not in order when the iteration completes. This isn't a problem if you're subsequently using only foreach loops, but if you need to use a for loop, you can put $input = array_values($input); after the above to renumber the keys.
try this solution for (n) Dimensional array with non-restricted length
for example this array
$arr= [
0 => [0=>"a" , 1=>"b" , 2=>"c" ] ,
1 => [0=>"x" , 1=>"b" , 2=>"a", 3=>"p"],
2=> [
[
0=>"y" ,
1=>"b" ,
2=> [0=>"x" , 1=>"m" , 2=>"a"]
],
1=>"z" ,
2=>"v"
]
];
This would be the solution
$ar2=[];
$ar3=[];
function test($arr){
global $ar2,$ar3;
if(is_array($arr)){
return array_map("test",$arr);
}
if(!isset($ar2[$arr])){
$ar2[$arr]=1;
$ar3[]=$arr;
}
}
array_map("test",$arr);
print_r($ar3);
Based on the Answer marked as correct, adding my answer. Small code added just to reset the indices-
$input = array_values(array_map("unserialize", array_unique(array_map("serialize", $inputArray))));
How can I remove duplicate values from a multi-dimensional array in PHP?
Example array:
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
[3] => Array
(
[0] => abc
[1] => def
)
[4] => Array
(
[0] => ghi
[1] => jkl
)
[5] => Array
(
[0] => mno
[1] => pql
)
)
Here is another way. No intermediate variables are saved.
We used this to de-duplicate results from a variety of overlapping queries.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Since 5.2.9 you can use array_unique() if you use the SORT_REGULAR flag like so:
array_unique($array, SORT_REGULAR);
This makes the function compare elements for equality as if $a == $b were being used, which is perfect for your case.
Output
Array
(
[0] => Array
(
[0] => abc
[1] => def
)
[1] => Array
(
[0] => ghi
[1] => jkl
)
[2] => Array
(
[0] => mno
[1] => pql
)
)
Keep in mind, though, that the documentation states:
array_unique() is not intended to work on multi dimensional arrays.
I had a similar problem but I found a 100% working solution for it.
<?php
function super_unique($array,$key)
{
$temp_array = [];
foreach ($array as &$v) {
if (!isset($temp_array[$v[$key]]))
$temp_array[$v[$key]] =& $v;
}
$array = array_values($temp_array);
return $array;
}
$arr="";
$arr[0]['id']=0;
$arr[0]['titel']="ABC";
$arr[1]['id']=1;
$arr[1]['titel']="DEF";
$arr[2]['id']=2;
$arr[2]['titel']="ABC";
$arr[3]['id']=3;
$arr[3]['titel']="XYZ";
echo "<pre>";
print_r($arr);
echo "unique*********************<br/>";
print_r(super_unique($arr,'titel'));
?>
Another way. Will preserve keys as well.
function array_unique_multidimensional($input)
{
$serialized = array_map('serialize', $input);
$unique = array_unique($serialized);
return array_intersect_key($input, $unique);
}
Array
(
[0] => Array
(
[id] => 1
[name] => john
)
[1] => Array
(
[id] => 2
[name] => smith
)
[2] => Array
(
[id] => 3
[name] => john
)
[3] => Array
(
[id] => 4
[name] => robert
)
)
$temp = array_unique(array_column($array, 'name'));
$unique_arr = array_intersect_key($array, $temp);
This will remove the duplicate names from array. unique by key
If "remove duplicates" means "remove duplicates, but let one there", a solution might be to apply the array_unique(...) on the "identifier column" first and then to remove in the original array all the keys, that have been removed from the column array:
$array = [
[
'id' => '123',
'foo' => 'aaa',
'bar' => 'bbb'
],
[
'id' => '123',
'foo' => 'ccc',
'bar' => 'ddd'
],
[
'id' => '567',
'foo' => 'eee',
'bar' => 'fff'
]
];
$ids = array_column($array, 'id');
$ids = array_unique($ids);
$array = array_filter($array, function ($key, $value) use ($ids) {
return in_array($value, array_keys($ids));
}, ARRAY_FILTER_USE_BOTH);
The result is:
Array
(
[0] => Array
(
[id] => 123
[foo] => aaa
[bar] => bbb
)
[2] => Array
(
[id] => 567
[foo] => eee
[bar] => fff
)
)
The user comments on the array_unique() documentation have many solutions to this. Here is one of them:
kenrbnsn at rbnsn dot com
27-Sep-2005 12:09
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.
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);
}
This is from http://ca3.php.net/manual/en/function.array-unique.php#57202.
if you need to eliminate duplicates on specific keys, such as a mysqli id, here's a simple funciton
function search_array_compact($data,$key){
$compact = [];
foreach($data as $row){
if(!in_array($row[$key],$compact)){
$compact[] = $row;
}
}
return $compact;
}
Bonus Points
You can pass an array of keys and add an outer foreach, but it will be 2x slower per additional key.
if you have an array like this:
(users is the name of the array)
Array=>
[0] => (array)
'user' => 'john'
'age' => '23'
[1] => (array)
'user' => 'jane'
'age' => '20'
[2]=> (array)
'user' => 'john'
'age' => '23'
and you want to delete duplicates...then:
$serialized = array();
for ($i=0; $i < sizeof($users); $i++) {
$test = in_array($users['user'], $serialized);
if ($test == false) {
$serialized[] = $users['user'];
}
}
can be a solution :P
Lots of person asked me how to make Unique multidimensional array. I have taken reference from your comment and it helps me.
First of All, Thanks to #jeromegamez #daveilers for your solution. But every time i gave the answer, they asked me how this 'serialize' and 'unserialize' works. That's why i want to share the reason of this with you so that it will help more people to understand the concept behind this.
I am explaining why we use 'serialize' and 'unserialize' in steps :
Step 1: Convert the multidimensional array to one-dimensional array
To convert the multidimensional array to a one-dimensional array, first generate byte stream representation of all the elements (including nested arrays) inside the array. serialize() function can generate byte stream representation of a value. To generate byte stream representation of all the elements, call serialize() function inside array_map() function as a callback function. The result will be a one dimensional array no matter how many levels the multidimensional array has.
Step 2: Make the values unique
To make this one dimensional array unique, use array_unique() function.
Step 3: Revert it to the multidimensional array
Though the array is now unique, the values looks like byte stream representation. To revert it back to the multidimensional array, use unserialize() function.
$input = array_map("unserialize", array_unique(array_map("serialize", $input)));
Thanks again for all this.
A very easy and logical way to Unique a multi dimension array is as follows,
If you have array like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value1
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value1
[3] => Value3
[4] => Value4
)
)
use foreach to solve this:
foreach($array as $k=>$v){
$unique=array_unique($v);
$array[$k]=$unique;
}
it will give you following result:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[3] => Value3
[4] => Value4
)
)
and if you want to rearrange the order of the keys,
foreach($array as $k=>$v){
$unique= array_values(array_unique($v));
$array[$k]=$unique;
}
This operation will give you arranged key values like this:
Array
(
[Key1] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
)
[Key2] => Array
(
[0] => Value1
[1] => Value2
[2] => Value3
[3] => Value4
)
)
I hope this will clear everything.
An easy to read solution, probably not the most efficient:
function arrayUnique($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;
}
As people are saying array_unique() is very slow, here is a snippet I use for one level multidimensional array.
$serialized_array = array_map("serialize", $input);
foreach ($serialized_array as $key => $val) {
$result[$val] = true;
}
$output = array_map("unserialize", (array_keys($result)));
Reference first user contributed note of array_unique() function page in php.net
This solution is relevant only when uniqueness is needed for one array column, for example here if we need the uniqueness in index #0 of the arrays.
Solution #1:
Using array_filter with an anonymous function and a static variable:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$list = array_filter($list, function ($item) {
static $values = [];
if (!in_array($item[0], $values)) {
$values[] = $item[0];
return true;
} else {
return false;
}
});
var_dump($list);
Solution #2:
Since the value when we want the uniqueness are of string type, we can remap the original global array to use these values as keys, which will remove duplicates as we remap it:
<?php
$list = [
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql'],
['abc', 'def'],
['ghi', 'jkl'],
['mno', 'pql']
];
$unique = [];
foreach ($list as $item) {
$unique[$item[0]] = $item;
}
// Remap again to integers
$unique = array_values($unique);
var_dump($unique);
An alternative to serialize and unique
$test = [
['abc','def'],
['ghi','jkl'],
['mno','pql'],
['abc','def'],
['ghi','jkl'],
['mno','pql'],
];
$result = array_reduce(
$test,
function($carry,$item){
if(!in_array($item,$carry)) {
array_push($carry,$item);
}
return $carry;
},
[]
);
var_dump($result);
/*
php unique.php
array(3) {
[0] =>
array(2) {
[0] =>
string(3) "abc"
[1] =>
string(3) "def"
}
[1] =>
array(2) {
[0] =>
string(3) "ghi"
[1] =>
string(3) "jkl"
}
[2] =>
array(2) {
[0] =>
string(3) "mno"
[1] =>
string(3) "pql"
}
}
*/
I've given this problem a lot of thought and have determined that the optimal solution should follow two rules.
For scalability, modify the array in place; no copying to a new array
For performance, each comparison should be made only once
With that in mind and given all of PHP's quirks, below is the solution I came up with. Unlike some of the other answers, it has the ability to remove elements based on whatever key(s) you want. The input array is expected to be numeric keys.
$count_array = count($input);
for ($i = 0; $i < $count_array; $i++) {
if (isset($input[$i])) {
for ($j = $i+1; $j < $count_array; $j++) {
if (isset($input[$j])) {
//this is where you do your comparison for dupes
if ($input[$i]['checksum'] == $input[$j]['checksum']) {
unset($input[$j]);
}
}
}
}
}
The only drawback is that the keys are not in order when the iteration completes. This isn't a problem if you're subsequently using only foreach loops, but if you need to use a for loop, you can put $input = array_values($input); after the above to renumber the keys.
try this solution for (n) Dimensional array with non-restricted length
for example this array
$arr= [
0 => [0=>"a" , 1=>"b" , 2=>"c" ] ,
1 => [0=>"x" , 1=>"b" , 2=>"a", 3=>"p"],
2=> [
[
0=>"y" ,
1=>"b" ,
2=> [0=>"x" , 1=>"m" , 2=>"a"]
],
1=>"z" ,
2=>"v"
]
];
This would be the solution
$ar2=[];
$ar3=[];
function test($arr){
global $ar2,$ar3;
if(is_array($arr)){
return array_map("test",$arr);
}
if(!isset($ar2[$arr])){
$ar2[$arr]=1;
$ar3[]=$arr;
}
}
array_map("test",$arr);
print_r($ar3);
Based on the Answer marked as correct, adding my answer. Small code added just to reset the indices-
$input = array_values(array_map("unserialize", array_unique(array_map("serialize", $inputArray))));
I have 2 arrays:
$arr1 = array('Test', 'Hello', 'World', 'Foo', 'Bar1', 'Bar'); and
$arr2 = array('hello', 'Else', 'World', 'Tes', 'foo', 'BaR1', 'Bar');
I need to compare the 2 arrays and save the position of the matching elements to a 3rd array $arr3 = (3, 0, 2, 4, 5, 6); //expected result, displaying position of matching element of $arr1 in $arr2.
By 'matching' I mean all elements that are identical (ex. World), or partially the same (ex. Test & Tes) and also those elements that are alike but are in different case (ex. Foo & foo, Bar & bar).
I've tried a series of combinations and of various functions without success, using functions like array_intersect(), substr_compare(), array_filter() and more. I'm not asking for the exact solution, just something to get me on the right track because i'm going around in circles all afternoon.
This seemed to work for me, but I'm sure there are some edge cases I'm missing that you'd need to test for:
foreach( $arr1 as $i => $val1) {
$result = null;
// Search the second array for an exact match, if found
if( ($found = array_search( $val1, $arr2, true)) !== false) {
$result = $found;
} else {
// Otherwise, see if we can find a case-insensitive matching string where the element from $arr2 is at the 0th location in the one from $arr1
foreach( $arr2 as $j => $val2) {
if( stripos( $val1, $val2) === 0) {
$result = $j;
break;
}
}
}
$arr3[$i] = $result;
}
It produces your desired output array:
Array ( [0] => 3 [1] => 0 [2] => 2 [3] => 4 [4] => 5 [5] => 6 )
Try array_uintersect() with a callback function that implements your "matching" algorithm.
Looks like you need 2 foreach loops, and stripos (or mb_stripos for Unicode) for comparing.
I came up with this to account for duplicates. It returns both keys and both values so you can compare to see if it's working properly. To refine it, you can just comment out the lines setting the values you don't need. It matches all cases.
<?php
$arr1 = array('Test', 'Hello', 'World', 'Foo', 'Bar1', 'Bar');
$arr2 = array('hello', 'Else', 'World', 'Tes', 'foo', 'BaR1', 'Bar');
$matches = array();
//setup the var for the initial match
$x=0;
foreach($arr1 as $key=>$value){
$searchPhrase = '!'.$value.'!i';
//Setup the var for submatching (in case there is more than one)
$y=0;
foreach($arr2 as $key2=>$value2){
if(preg_match($searchPhrase,$value2)){
$matches[$x][$y]['key1']=$key;
$matches[$x][$y]['key2']=$key2;
$matches[$x][$y]['arr1']=$value;
$matches[$x][$y]['arr2']=$value2;
}
$y++;
}
unset($y);
$x++;
}
print_r($matches);
?>
Output looks like this:
Array
(
[1] => Array
(
[0] => Array
(
[key1] => 1
[key2] => 0
[arr1] => Hello
[arr2] => hello
)
)
[2] => Array
(
[2] => Array
(
[key1] => 2
[key2] => 2
[arr1] => World
[arr2] => World
)
)
[3] => Array
(
[4] => Array
(
[key1] => 3
[key2] => 4
[arr1] => Foo
[arr2] => foo
)
)
[4] => Array
(
[5] => Array
(
[key1] => 4
[key2] => 5
[arr1] => Bar1
[arr2] => BaR1
)
)
[5] => Array
(
[5] => Array
(
[key1] => 5
[key2] => 5
[arr1] => Bar
[arr2] => BaR1
)
[6] => Array
(
[key1] => 5
[key2] => 6
[arr1] => Bar
[arr2] => Bar
)
)
)
My First Array Look Like This
$array1 = array('0' => 'news', '1' => 'game');
Array
(
[0] => news
[1] => game
)
My Second Array Look Like This
$array2 = array('0' => '1', '1' => '2');
Array
(
[0] => 1
[1] => 2
)
I Need Output Like This
$array3 = array(array('0'=>'new', '1'=>'1'),array('0'=>'game', '1'=>'2'));
Array
(
[0] => Array
(
[0] => new
[1] => 1
)
[1] => Array
(
[0] => game
[1] => 2
)
)
I tried multiple way using array_merge, array_merge_recursive and loop
but not getting the proper output.
Here's an easy way:
$result = array_map(null, $array1, $array2);
This will work regardless of the indexes, so in your case, for better or worse, these would also produce the same result:
$array1 = array(1 => 'news', 5 => 'game');
$array2 = array(2 => '1', 6 => '2');
You can use array_map for this, with null as first argument:
$result = array_map(null, $first_array, $second_array);
use this code
$array1 = array_values($array1);
$array2 = array_values($array2);
$array = [];
$count = count($array1);
for($i=0;$i<$count;$i++)
$array[] = [$array1[$i] , $array2[$i]];
var_dump($array);
Lot's of ways to do this, array_map as other's have answered is probably your best bet. IF you want to see what's happening:
foreach($array1 as $key => $value){
$array3[$key] = array($value, $array2[$key]);
}