Transforming arrays into the correct formats

Question

I am still attempting to learn how to best handle arrays and iterate their values transforming them into the correct formats that are needed for my database/API.

So I have this array:

$arr = [
 0 => [
 'field' => [
 0 => [
 '@name' => 'first_name',
 '@value' => 'Jack'
 ],
 1 => [
 '@name' => 'last_name',
 '@value' => 'Lew'
 ],
 2 => [
 '@name' => 'email',
 '@value' => '[email protected]'
 ]
 ]
 ]
];

And I need it to look like this:

[0] => Array
 (
 [first_name] => Jack
 [last_name] => Lew
 [email] => [email protected]
 )

To get to this I have taken the same approach I usually take:

for( $i = 0; $i < count($arr); $i++ ) {
 foreach($arr[$i] as $k => $v) {
 print_r($k . ': \r\n');
 if( is_array($v) ) {
 foreach($v as $key => $val) {
 $new[$i][$val['@name']] = $val['@value'];
 }
 }
 }
}

The problem I having here is, I believe there has to be a better way to achieve the same results without being three levels deep of loops, since they are slower and just harder to debug altogether.

I would appreciate any insights on how I can make this code better in both readability and performance.

Answer 1

If you know that the key field exists, you could use array_map() to apply a function on each row. This function could use array_column() to transform a column as keys, and another as values:

$arr = [
 [
 'field' => [
 ['@name' => 'first_name', '@value' => 'Jack'],
 ['@name' => 'last_name', '@value' => 'Lew'],
 ['@name' => 'email', '@value' => '[email protected]']
 ]
 ],
 [
 'field' => [
 ['@name' => 'first_name', '@value' => 'John'],
 ['@name' => 'last_name', '@value' => 'Doe'],
 ['@name' => 'email', '@value' => '[email protected]']
 ]
 ]
];
$data = array_map(function($item) {
 return array_column($item['field'], '@value', '@name');
}, $arr) ;
print_r($data);

Output:

Array
(
 [0] => Array
 (
 [first_name] => Jack
 [last_name] => Lew
 [email] => [email protected]
 )
 [1] => Array
 (
 [first_name] => John
 [last_name] => Dow
 [email] => [email protected]
 )
)

• sam: I like that, I like that very much... You may want to swap '@value' and '@name' in the array_column function. Since I want the key as the identifier, and the value in the value place.
• Syscall: Oh yes, you're right @Samuel. I'll update the answer. Thank you!