CODEWITHSUNDEEP
phparraysmultidimensional-arrayfilterintersection
Compiler
Compiler

Reputation: 111

Get intersecting rows from two 2d arrays

I am trying to get the intersection of two or more arrays with this kind of structure:

First array:

array(
    [0] => array(
        ['room_id'] => 21
        ['room_name'] => 'GB 101'
        ['capacity'] => 40
    )
    [1] => array(
        ['room_id'] => 22
        ['room_name'] => 'H 114'
        ['capacity'] => 20
    )
    [2] => array(
        ['room_id'] => 23
        ['room_name'] => 'GB 203'
        ['capacity'] => 20
    )
    [3] => array(
        ['room_id'] => 25
        ['room_name'] => 'H 100'
        ['capacity'] => 30
    )
    [4] => array(
        ['room_id'] => 26
        ['room_name'] => 'GB 206'
        ['capacity'] => 40
    )
)

Second Array:

array(
    [0] => array(
        ['room_id'] => 21
        ['room_name'] => 'GB 101'
        ['capacity'] => 40
    )
    [1] => array(
        ['room_id'] => 23
        ['room_name'] => 'GB 203'
        ['capacity'] => 20
    )
    [2] => array(
        ['room_id'] => 26
        ['room_name'] => 'GB 206'
        ['capacity'] => 40
    )
)

Resulting array:

array(
    [0] => array(
        ['room_id'] => 21
        ['room_name'] => 'GB 101'
        ['capacity'] => 40
    )
    [1] => array(
        ['room_id'] => 23
        ['room_name'] => 'GB 203'
        ['capacity'] => 20
    )
    [2] => array(
        ['room_id'] => 26
        ['room_name'] => 'GB 206'
        ['capacity'] => 40
    )
)

I tried using array_intersect_assoc to get the intersection using the following code:

$result = call_user_func_array('array_intersect_assoc', $arrays);

It does the trick but it gives the following warning which is expected according here:

A PHP Error was encountered

Severity: Notice

Message: Array to string conversion

I am making an Ajax based system so the error messes it up. Is there any way to get the intersection of the arrays?

Upvotes: 0

Views: 712

Answers (3)

AbraCadaver
AbraCadaver

Reputation: 78974

Try serializing them:

$result = array_map('unserialize',
              array_intersect(
                  array_map('serialize', $first), array_map('serialize', $second)));
  • array_map() runs each sub-array of the main arrays through serialize() which converts each sub-array into a string representation of that sub-array
    • the main arrays now have values that are not arrays but string representations of the sub-arrays
  • array_intersect() now has a one-dimensional array for each of the arrays to compare
  • after the intersection is returned array_map() runs the array result (intersection) through unserialize() to turn the string representations back into sub-arrays

Upvotes: 3

Kanishka Panamaldeniya
Kanishka Panamaldeniya

Reputation: 17586

To compare two multidimensional arrays , a simple solution would be

$new_array = array();
foreach($array1 as $sub_array1)
{
   foreach($array2 as $sub_array2)
   {
       if($sub_array1 === $sub_array2)
       {
            $new_array[] = $sub_array2;
       }
   }
}

print_r($new_array);

Upvotes: 0

PHPhil
PHPhil

Reputation: 1540

Use array_uintersect() to use a custom comparison function, for example compare by room_id.

<?php
$array1 = array(
    "0" => array(
        "room_id" => 21,
        "room_name" => 'GB 101',
        "capacity" => 40
    ),
    "1" => array(
        "room_id" => 22,
        "room_name" => 'H 114',
        "capacity" => 20
    ),
    "2" => array(
        "room_id" => 23,
        "room_name" => 'GB 203',
        "capacity" => 20
    ),
    "3" => array(
        "room_id" => 25,
        "room_name" => 'H 100',
        "capacity" => 30
    ),
    "4" => array(
        "room_id" => 26,
        "room_name" => 'GB 206',
        "capacity" => 40
    )
);

$array2 = array(
    "0" => array(
        "room_id" => 21,
        "room_name" => 'GB 101',
        "capacity" => 40
    ),
    "1" => array(
        "room_id" => 23,
        "room_name" => 'GB 203',
        "capacity" => 20
    ),
    "2" => array(
        "room_id" => 26,
        "room_name" => 'GB 206',
        "capacity" => 40
    )
);

$intersect = array_uintersect($array1, $array2, 'compareDeepValue');

function compareDeepValue($val1, $val2)
{
   return strcmp($val1['room_id'], $val2['room_id']);
}

echo "<pre>";
print_r($intersect);

?>

output:

Array
(
    [0] => Array
        (
            [room_id] => 21
            [room_name] => GB 101
            [capacity] => 40
        )    
    [1] => Array
        (
            [room_id] => 23
            [room_name] => GB 203
            [capacity] => 20
        )    
    [2] => Array
        (
            [room_id] => 26
            [room_name] => GB 206
            [capacity] => 40
        )    
)

Upvotes: 0

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