How can I search for value to get key and use that key to get another key in a different array?

Question

I have a large associative array with many keys and values that looks like this. I want to search for a specific value "Often" and retrieve all of the keys that have that value.

$data = array(
'token' => 'token',
'content' => 'record',
'format' => 'json',
'type' => 'flat',
'records' => array($record),
'fields' => array(),
'returnFormat' => 'json'
);
 $ch = curl_init();
 curl_setopt($ch, CURLOPT_URL, 'url');
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
 curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
 curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
 curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);
 curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data, '', '&'));
$output = curl_exec($ch);
$row = json_decode($output, true);

foreach ($row[0] as $key => $value) {

              $first_array=array($variable_name=>$value);

              $often_variable=array_search("Often <br> (3)", $first_array);                 
          }

Then, I want to use my second array that has that key as its value and print out the keys of that array into a table.

  $objPHPExcel = PHPExcel_IOFactory::load("123.csv");

 foreach ($objPHPExcel->getWorksheetIterator() as $worksheet) {
$worksheetTitle     = $worksheet->getTitle();
$highestRow         = $worksheet->getHighestRow(); // e.g. 10
$highestColumn      = $worksheet->getHighestColumn(); // e.g 'F'
$highestColumnIndex = PHPExcel_Cell::columnIndexFromString($highestColumn);
$nrColumns = ord($highestColumn) - 64;

for ($row2 = 2; $row2 <= $highestRow; ++ $row2) {
    $variable_name = $worksheet->getCellByColumnAndRow(0, $row2)->getValue();
    $field_label = $worksheet->getCellByColumnAndRow(4, $row2)->getValue();

    $second_array=array($field_label=>$variable_name)
}

I've used array_search() but not sure if this is the best option for this use case.

Answer 1

  foreach ($first_array as $var_name => $val){
    if ($value == "Often"){
      foreach ($second_array as $field_label => $variable_name){
         if ($variable_name == $var_name){
           echo "field_label: $field_label\n";
         };
      }
    }
  }