将$ msgArray附加到现有数组

Is it possible to assign $msgArray as a last element of the array which is used in curl

foreach( $attachmentsArray as $att )
    {
        $msgArray["attachment[$x]"] = curl_file_create( $att );
        $x ++;
    }
 curl_setopt($ch, CURLOPT_POSTFIELDS, array(
  'from' => 'Open <test@gmail.com>',
  'to' => $email,
  'subject' => $subject,
  'html' => $msg
));

Yes. Just as a pump, does this work for you?

foreach( $attachmentsArray as $att )
    {
        $msgArray["attachment[$x]"] = curl_file_create( $att );
        $x ++;
    }

$arrayValues = array(
  'from' => 'Open <test@gmail.com>',
  'to' => $email,
  'subject' => $subject,
  'html' => $msg,
  'attachments' => http_build_query($msgArray)

  /** or an alternative form of collapsing an array into a
     string value, such as json_encode($msgArray);  **/
);


 curl_setopt($ch, CURLOPT_POSTFIELDS, $arrayValues);

reference (recommended)