I have two arrays of associative arrays with different keys. I need to merge them into a single array of associative arrays, with nulls or empty strings for keys that do not exist at higher indices. For example:
$first = array(array('x'=>'1','y'=>'2'));
$second = array(array('z'=>'3'),array('z'=>'4'));
The result should look like this:
$result = array(
array(
'x'=>'1',
'y'=>'2',
'z'=>'3'
),
array(
'x'=>'',
'y'=>'',
'z'=>'4'
)
);
The function that merges these arrays needs to be able to handle two or more arrays. Here's what I came up with:
// allArrays can be many arrays of all sizes and will be different each time this process runs
$allArrays = array($first, $second);
$longestArray = max($allArrays);
$data = array();
for($i = 0; $i < count($longestArray); ++$i) {
$dataRow = array();
foreach ($allArrays as $currentArray) {
if (isset($currentArray[$i])) {
foreach ($currentArray[$i] as $key => $value) {
$dataRow[$key] = $value;
}
} else {
foreach ($currentArray[0] as $key => $value) {
$dataRow[$key] = '';
}
}
}
$data[] = $dataRow;
}
It works, but I think the nested for loops cause poor performance on large arrays, and it's pretty illegible. Is there a better way to tackle this problem?