Merge two array into one into chunks

Question

I have the following arrays

$arr1 = array( 
           array('ctype'=>'fr', 'type'=>'fr'), 
           array('ctype'=>'fasdf', 'type'=>'fr'), 
           array('ctype'=>'fdfdf', 'type'=>'fr'), 
           array('ctype'=>'fhjdf', 'type'=>'fr'), 
           array('ctype'=>'fsf', 'type'=>'fr'), 
           array('ctype'=>'vndf', 'type'=>'fr'), 
           array('ctype'=>'fnsdf', 'type'=>'fr')
);

$arr2 = array( 
          array('ctype'=>'fr', 'type'=>'ln'), 
          array('ctype'=>'fasdf', 'type'=>'ln'), 
          array('ctype'=>'fayf', 'type'=>'ln'), 
          array('ctype'=>'fauf', 'type'=>'ln')
);

I want to merge this array into one but into chunks with difference of 2 something like

$main_arr = array(
              array('ctype'=>'fr', 'type'=>'fr'), 
              array('ctype'=>'fasdf', 'type'=>'fr'), 
              array('ctype'=>'fr', 'type'=>'ln'), 
              array('ctype'=>'fasdf', 'type'=>'ln'), 
              array('ctype'=>'fdfdf', 'type'=>'fr'), 
              array('ctype'=>'fhjdf', 'type'=>'fr'), 
              array('ctype'=>'fayf', 'type'=>'ln'), 
              array('ctype'=>'fauf', 'type'=>'ln')
              array('ctype'=>'fsf', 'type'=>'fr'), 
              array('ctype'=>'vndf', 'type'=>'fr'), 
              array('ctype'=>'fnsdf', 'type'=>'fr')
 );

As you see i want to take 2 values from arr1 then 2 from arr2 and if the value not exists in like the example $arr2 then get and push the values from $arr1 . I tried it with array_chunks and array_map but can't get the expected.

This is what i tried:

// Divide foursome into chunks
$fr = array_chunk($arr1, 2);
$ln = array_chunk($arr2, 2);

// Can't provide the expected result
$main = array_map(NULL, $fr, $ln);

Answer 1

I think you're after something like this:

function combine($a1, $a2) {
    if (is_array($a2) && count($a2)) {
        $a1 = array_merge($a1, $a2);
    }
    return $a1;
}

$m = array_map('combine', $fr, $ln);

$main = array();
foreach ($m as $idx => $ars) {
    $main = array_merge($main, $ars);
}

The first point to note is that the number of arrays passed to array_map() has to match the number of parameters taken by your callback function.

The second point to note is that "chunking" adds a new level to your array, so you need some way to "flatten" the result of combining the two "chunked" arrays.