PHP - split one array into 2 array based on key value pair [duplicate]

You can create temporary arrays:

$arr = json_decode($str, true);

foreach($arr as $a){
    if($a['test_type'] == 'Radiology'){
        $radiology_array[] = $a;
    }
    if($a['test_type'] == 'Pathology'){
        $pathology_array[] = $a;
    }
    ...
}

You can use array_column to make a flat array of the type which you the use as the matching array.
When you loop the matching array ($type) you can use array_intersect to get the subarrays as you wanted.

I place them in an associative array that can be extracted to new variables.

$arr = json_decode($json,true);
$type = array_column($arr, "test_type");

Foreach(array_unique($type) as $t){
   $new[$t] = array_intersect_key($arr, array_intersect($type, [$t]));
}
extract($new);
var_dump($Radiology, $Pathology);

https://3v4l.org/nj936

This method will only loop the unique count of types and will work even if you add a new type to the list like: https://3v4l.org/Jf0SE

I believe this is JSON format.

Just use the old json_decode($variable) and assign each key to another variable.

$result = json_decode($variable);

$type = [];
foreach ($result as $item) {
    $type[$item->test_type][] = $item;     
}

This way, each test_type will have it's own key. Which could be used as one array for each test_type.