PHP: Fast way to combine 2 arrays (insert every element from B into one specific element of A)

Question

i got 2 multidimensional arrays A and B. Every element of A has a counterpart in B. I want to combine those 2 part.

Does php has a method to do such a task.

Running 2 loops and checking for a match seems a bit inefficient.

Example:

$a = array(
     '0' => array(
          'id' = 1,
          'value_a' = 'v1'),
     '1' => array(
          'id' = 2,
          'value_a' = 'v2'),
     '2' => array(
          'id' = 3,
          'value_a' = 'v3'),

$b = array(
     '0' => array(
          'a_id' = 3,
          'value_b' = 'v3'),
     '1' => array(
          'a_id' = 1,
          'value_b' = 'v1'),
     '2' => array(
          'a_id' = 2,
          'value_b' = 'v2')

Result:

 $c = array(
     '0' => array(
          'id' = 3,
          'value_a' = 'v3'),
          'a_id' = 3,
          'value_b' = 'v3'),
     '1' => array(
          'id' = 1,
          'value_a' = 'v1'),
          'a_id' = 1,
          'value_b' = 'v1'),
     '2' => array(
          'id' = 2,
          'value_a' = 'v2'),
          'a_id' = 2,
          'value_b' = 'v2')

Update

Loopmethod:

foreach ($a as $a_item) {
     foreach ($b as $b_item) {
         if ($a_item['id'] == $b_item['a_id']) {
              $c[] = array_merge($a_item, $b_item);
         }
     }
}

Thx

Can you format the arrays properly so I can help. – Oct 06 '14 at 18:41 — , Oct 06 '14 at 18:41
better formation and the loopmethod added – Cheetah Oct 06 '14 at 18:58 — Cheetah, Oct 06 '14 at 18:58

score 1 · Answer 1 · answered Oct 06 '14 at 18:46

1

You actually want to merge the values of the parent array.PHP has no built in method as such to perform your task, but you can:

$combined_array = array_map(function($arr1, $arr2) { return array_merge($arr1, $arr2); }, $A, $B));

answered Oct 06 '14 at 18:46

Sameer Shemna

886
10
19

the order of both arrays is random so what would insure the right elements are matched – Cheetah Oct 06 '14 at 19:05

score 0 · Answer 2 · answered Oct 06 '14 at 18:46

0

just 1 loop and array_merge

$result = array();
foreach($a as $k=>$v){
    $result[] = array_merge($v, $b[$k]);
}

answered Oct 06 '14 at 18:46

Marin Vartan

572
7
16

the elements in $a and $b which belong together, dont have the same key $k – Cheetah Oct 06 '14 at 19:04

PHP: Fast way to combine 2 arrays (insert every element from B into one specific element of A)

2 Answers2