PHP - How to compare arrays and extract the difference?

Question

I have two arrays that I would like to compare and ultimately wind up with a single array with everything combined, having no duplicates. Can someone please tell me which function I should use? There are so many that it's a bit confusing.

$array1[]['name'] = 'Kim, Jones';
$array1[]['name'] = 'Jim, Miller';

array1 is an array I built that I want added to an array coming from the database. The key in the second array is also named "name". Thanks.

EDIT:

I managed to merge these two arrays but I can still see duplicates.

This is what the first array looks like:

Array
(
    [0] => Array
        (
            [WNumber] => ADMIN
            [Name] => Tim, Cooley
            [Employer] => CalPERS
            [Student] => 1
            [Perm] => 1
            [QA] => 0
            [Supervisor] => 1
            [RQW] => 0
        )

My second array is built like this:

$add_names[]['Name']='Jim, Jones';

I just want to add $add_names to the first array WHERE there are no duplicates.

Answer 1

Does php's array_diff() do what you want?

http://us.php.net/manual/en/function.array-diff.php

or more likely array_diff_assoc:

http://us.php.net/manual/en/function.array-diff-assoc.php

Answer 2

Does array_diff work for you?

Description

array array_diff ( array $array1 , array $array2 [, array $ ... ] )
Compares array1 against array2 and returns the difference.

Answer 3

I think you'll need to use a combination of array_merge (adds the two arrays together) and array_unique (removes duplicate values).

$resulting_array = array_unique(array_merge($array1, $array2));

Note that array_unique will not work correctly when using multi-dimensional arrays, so if your array data looks the way you put it in your question, you'll have to think of a way around that. One of the comments on the array_unique page suggests serialize'ing all array values before running array_unique on it. Afterwards you'd just run unserialize on all array elements. Note that this can mean a performance hit if you have a big array, so you might want to consider avoiding multi-dimensional arrays in this scenario.

Something like this:

$merged_array = array_merge($array1, $array2);
$serialized_array = array_map("serialize", $merged_array);
$filtered_array = array_unique($serialized_array);
$final_array = array_map("unserialize", $filtered_array);

Answer 4

I'm tempted to sell you on CakePHP, since it has a number of functions that makes this easy in its "Set" class. Your problem is that you have the results in a nested array. A simple "array_unique" does not work in a nested array.

I'd do it the old fashioned way...

$array1[]['name'] = 'Kim, Jones';
$array1[]['name'] = 'Jim, Miller';

$array2[]['name'] = 'Kim, Jones';
$array2[]['name'] = 'Jimbo, Miller';
$array2[]['name'] = 'Jim, Jones';

$new_array=array_merge($array1, $array2);
$out_array = array();
$key_array = array();
foreach($new_array as $i => $row) {
        if (empty($key_array[$row['name']])) {
                $out_array[] = $row;
        }
        $key_array[$row['name']] = 1;
}

print_r($out_array);

This code works for me...

Answer 5

There isn't a direct function for handling what you are looking for in php, probably you need to write a function for it.

What I understood from your question is that you have 2 arrays :

$a = array( array( 'name' => 'Omid' ), 12 );
$b = array( array( 'name' => 'testing' ) );

and you want to merge them to get

$merge = array( array( 'name' => 'testing' ), 12 );

if that's what you want then you might want to take a look at this comment array merge recursive which leads to this code :

function array_merge_recursive_distinct ( array &$array1, array &$array2 )
{
  $merged = $array1;

  foreach ( $array2 as $key => &$value )
  {
    if ( is_array ( $value ) && isset ( $merged [$key] ) && is_array ( $merged [$key] )     )
    {
      $merged [$key] = array_merge_recursive_distinct ( $merged [$key], $value );
    }
    else
    {
      $merged [$key] = $value;
    }
  }

  return $merged;
}