PHP - Merging two arrays into one array (also Remove Duplicates)

Question

Hi I'm Trying to merge two arrays and also want to remove duplicate values from final Array.

Here is my Array 1:

Array
    (
    [0] => stdClass Object
    (
    [ID] => 749
    [post_author] => 1
    [post_date] => 2012-11-20 06:26:07
    [post_date_gmt] => 2012-11-20 06:26:07
)

And this is my array 2:

Array
(
[0] => stdClass Object
(
[ID] => 749
[post_author] => 1
[post_date] => 2012-11-20 06:26:07
[post_date_gmt] => 2012-11-20 06:26:07

)

I'm using array_merge for merging both arrays into one array. it is giving output like this

Array
(
[0] => stdClass Object
(
[ID] => 749
[post_author] => 1
[post_date] => 2012-11-20 06:26:07
[post_date_gmt] => 2012-11-20 06:26:07

[1] => stdClass Object
(
[ID] => 749
[post_author] => 1
[post_date] => 2012-11-20 06:26:07
[post_date_gmt] => 2012-11-20 06:26:07

)

I want to remove these duplicate entries or can I remove these before merging... Pleas help.. Thanks!!!!!!!

Because you wanna merge $array1[0] and $array2[0] not $array1 and $array2. Try to run array_merge on the first item of each array — Bgi
– Bgi, Commented Nov 20, 2012 at 9:11
array is dynamic .. so it will not always $array1[0] and $array2[0] — Ravikumar Sharma
– Ravikumar Sharma, Commented Nov 20, 2012 at 9:12
is there anything with which I can compare ID of each object inside an array??? — Ravikumar Sharma
– Ravikumar Sharma, Commented Nov 20, 2012 at 9:13
Forget my first comment that won't work because what you're tryin to merge are not arrays but objects. You've to do it manually — Bgi
– Bgi, Commented Nov 20, 2012 at 9:16

Community · Accepted Answer · 2023-11-17 20:16:56Z

319

array_unique(array_merge($array1,$array2), SORT_REGULAR);

https://www.php.net/manual/en/function.array-unique.php

edited Nov 17, 2023 at 20:16

CommunityBot

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answered Nov 20, 2012 at 9:14

C. E.

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4 Comments

Ravikumar Sharma Over a year ago

@ Hemantxp > with out SORT_REGULAR it is giving this error: Catchable fatal error: Object of class stdClass could not be converted to string

Mike Over a year ago

Its worth noting that array_unique returns the filtered array (rather than acting directly on the array parameter passed in) so you need to store the result before you can use it

David Baucum Over a year ago

By default array_unique tries to use the array values as strings. Hence the error @Ravi ran into. If your array is only strings then you don't need the third argument. If it is not a string, or the contents cannot be implicitly cast to a string, you will need the SORT_REGULAR argument.

mapmath Over a year ago

@Hemantwagh07 For array objects, if we do not user SORT_REGULAR it gives Recoverable fatal error: Object of class stdClass could not be converted to string in...<path to file>

Nikola Petkanski · Accepted Answer · 2012-11-20 09:20:37Z

As already mentioned, array_unique() could be used, but only when dealing with simple data. The objects are not so simple to handle.

When php tries to merge the arrays, it tries to compare the values of the array members. If a member is an object, it cannot get its value and uses the spl hash instead. Read more about spl_object_hash here.

Simply told if you have two objects, instances of the very same class and if one of them is not a reference to the other one - you will end up having two objects, no matter the value of their properties.

To be sure that you don't have any duplicates within the merged array, Imho you should handle the case on your own.

Also if you are going to merge multidimensional arrays, consider using array_merge_recursive() over array_merge().

Divyesh · Accepted Answer · 2012-11-20 09:16:25Z

8

It will merger two array and remove duplicate

<?php
 $first = 'your first array';
 $second = 'your second array';
 $result = array_merge($first,$second);
 print_r($result);
 $result1= array_unique($result);
 print_r($result1);
 ?>

Try this link link1

answered Nov 20, 2012 at 9:16

Divyesh

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Comments

Jhonathan H. · Accepted Answer · 2012-11-20 09:15:23Z

4

try to use the array_unique()

this elminates duplicated data inside the list of your arrays..

answered Nov 20, 2012 at 9:15

Jhonathan H.

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Comments

Michal J Figurski · Accepted Answer · 2020-10-29 15:44:50Z

3

You can use this code to get the desired result. It will remove duplicates.

$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"green","g"=>"blue");

$result=array_unique(array_merge($a1,$a2));

print_r($result);

edited Oct 29, 2020 at 15:44

Michal J Figurski

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answered Oct 29, 2020 at 13:21

Usman Haider

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1 Comment

mickmackusa Over a year ago

This answer has oversimplified the asker's data. This task is not about merging flat arrays. This is about merging arrays of objects. Please use the asker's data when providing a solution/demonstration.

kantsverma · Accepted Answer · 2018-09-06 09:28:50Z

1

Merging two array will not remove the duplicate you can try the below example to get unique from two array

$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"green","g"=>"blue");

$result=array_diff($a1,$a2);
print_r($result);

answered Sep 6, 2018 at 9:28

kantsverma

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1 Comment

Warren Sergent Over a year ago

Whilst this will find ONLY unique entries (i.e. anything in both arrays will be removed), the OP question wanted to remove duplicates AFTER merge. So using your example, the desired result is red/green/blue/yellow kept from red/green/blue/yellow/red/green/blue after the two arrays are combined.

Tiago Peres · Accepted Answer · 2021-03-01 09:12:23Z

1

In my case I had to use ->toArray()

array_unique(array_merge($array1->toArray(),$array2->toArray()), SORT_REGULAR);

which results of combining both of these answers

answered Mar 1, 2021 at 9:12

Tiago Peres

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Comments

Phantom1412 · Accepted Answer · 2021-01-14 08:11:46Z

0

The best solution above faces a problem when using the same associative keys, array_merge() will merge array elements together when they have the same NON-NUMBER key, so it is not suitable for the following case

$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("c"=>"red","d"=>"black","e"=>"green");

If you are able output your value to the keys of your arrays instead (e.g ->pluck('name', 'id')->toArray() in Eloquent), you can use the following merge method instead

array_keys(array_merge($a1, $a2))

Basically what the code does is it utilized the behavior of array_merge() to get rid of duplicated keys and return you a new array with keys as array elements, hope it helps

answered Jan 14, 2021 at 8:11

Phantom1412

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1 Comment

mickmackusa Over a year ago

This answer has oversimplified the asker's data. This task is not about merging flat arrays. This is about merging arrays of objects. Please use the asker's data when providing a solution/demonstration.

Josep Alsina · Accepted Answer · 2022-11-03 11:39:58Z

0

In addition to the answer above, from PHP 7.4 you can make use of the spread operator:

array_unique([...$arr1, ...$arr2]);

answered Nov 3, 2022 at 11:39

Josep Alsina

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