Merge or combine an array like this? on PHP

Question

I have this multi-dimensional PHP array (below).

---

Array
(
    [0] => Array
        (
            [2] => [email protected]
        )

    [1] => Array
        (
            [4] => [email protected]
        )

    [2] => Array
        (
            [3908] => [email protected]
        )

    [3] => Array
        (
            [2548] => [email protected]
        )

    [4] => Array
        (
            [3099] => [email protected]
        )

    [5] => Array
        (
            [5283] => [email protected]
        )

)

---

I was wondering how could I merge? or combine? or simply do it like this using PHP (below).

---

Array
(
    [2] => [email protected]
    [4] => [email protected]
    [3908] => [email protected]
    [2548] => [email protected]
    [3099]  => [email protected]
    [5283]  => [email protected]
)

Help

Answer 1

The following will take your initial code and translate it to your desired output:

$new = array();
foreach($old as $key => $inner_array)
{
    $new += $inner_array;
}

(Where $old is your original)

This will retain keys and values. Note that this is making use of the array union operator +, and any duplicate keys in the target array will not be overwritten.

See the documentation page here for an explanation on why you won't use merge (3rd example):

array_merge

Answer 2

Simply go through the array and store to another.

$a = array( 0 => array(1) , 1=> array(3) );
$another=array();
foreach ($a as $k=>$v){    
    foreach ($v as $y=>$z){
        $another[$k]=$z;
    }    
}
print_r($another);

Answer 3

How about this?

foreach( $old_arr as $old )
{
    $key = key( $old[0] );
    $new[ $key ] = $old[0][$key];
}

EDIT: Never mind didn't realize previous answer was corrected.

Answer 4

You can "promote" the second level elements to first level elements via call_user_func_array(). And while array_merge() re-indexes the array, array_replace() does not but retains the original keys which makes this a one-liner:

$a = call_user_func_array('array_replace', $a);

test:

<?php
$a = array (
  array (2 => '[email protected]'),
  array (4 => '[email protected]'),
  array (3908 => '[email protected]'),
  array (2548 => '[email protected]'),
  array (3099 => '[email protected]'),
  array (5283 => '[email protected]'),
);
$a = call_user_func_array('array_replace', $a);
var_dump($a);