9

Starting Point

I have a multidimensional array, like the follow example:

$array = array (
  'role_1' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  ),
  'role_2' => 
  array (
    0 => 'value_1',
    1 => 'value_2',
  ),
  'role_3' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  ),
)

Goal

I like to loop about the sub-arrays to get only the intersection. The array was created dynamically, can have a lot of sub-arrays role_[x] and also a lot of key/value inside the sub-arrays. The key is not necessary, only the value. The key is also a count, not a string.

As a result, I like to get in this example this small array.

$array = array( 'value_2' )

The index, "the array-name", like role_1 of the sub-arrays is not more relevant after intersection. Important for me in the result is the values, only the values there are existed in each sub-array.

Attempt

I had tried with the source, but I think it is possible much simpler.

$value_stack = array();
$result = array();
$i = 0;
foreach( $settings_ as $role => $values ) {

    foreach( $values as $value ){

        if( in_array( $value,$value_stack ) || $i === 0 ) {
            $result[ $role ][] = $value;
        }

        $value_stack[] = $value;
    }
    $i++;

};

The merge of this multi array result should run with a array_merge in a loop.

Improve this question
2
  • $temp = $array[0]; for ($i = 1; $i < count($array) -1; $i++) { $temp = array_intersect($temp, $array[$i]); } Commented Jun 27, 2016 at 14:15
  • Thanks for your fast hint, but this is always NULL in my tests. Commented Jun 27, 2016 at 14:18

4 Answers 4

Reset to default
12

You can use array_intersect to cover the dynamic $data as such:

$data = array (
  'role_1' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  ),
  'role_2' => 
  array (
    0 => 'value_1',
    1 => 'value_2',
  ),
  'role_3' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  )
);

$result = call_user_func_array('array_intersect', $data);

call_user_func_array will help spread the elements of your array as parameters inside array_intersect.

Improve this answer
Sign up to request clarification or add additional context in comments.

1 Comment

array_intersect() does not accept unknown named parameters - PHP Version 8
7

You should be able to do

call_user_func_array('array_intersect', $array_of_arrays)

This will pass each element of your array of arrays as an argument to array_intersect, which takes a variable number of arrays as arguments and returns their intersection.

Improve this answer

4 Comments

The result of this is always NULL. I had tried this.
@bueltge Have you also tried with call_user_func_array?
Yes, sorry, it should have been call_user_func_array.
For the protocol: at first the answer was with the function call_user_func. The switch to call_user_func_array is really helpful. Thanks in advice!
1

array_intersect work for this:

$data = array (
  'role_1' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  ),
  'role_2' => 
  array (
    0 => 'value_1',
    1 => 'value_2',
  ),
  'role_3' => 
  array (
    0 => 'value_2',
    1 => 'value_3',
  )
);


$result = array_intersect($data['role_1'], $data['role_2'], $data['role_3']);
print_r($result);

result :

Array ( [0] => value_2 )
Improve this answer

1 Comment

I'd assume the number of roles is unknown, so this call style is a bit impractical.
0

As of PHP 5.6+ the splat/spread operator can be used to unpack the arguments in a call to array_intersect(). In order to remove the non-numeric keys from the array, pass $array to a call to array_values().

$result = array_intersect(...array_values($array));

See a demonstration in this playground example.

Improve this answer

Comments

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.