Php 从电子邮件中删除某些部分

大家好，我正在努力清除我gmail帐户中的所有电子邮件，我已经成功地做到了这一点，但我不明白的是，我想从电子邮件正文中获得某些部分，但我不明白我该如何做到这一点。这是我到现在为止所做的

<?php

/* connect to gmail */
$hostname = '{imap.gmail.com:993/imap/ssl}INBOX';
$username = 'ddum33165@gmail.com';
$password = 'abcde1234567890';

/* try to connect */
// try{
    $inbox = imap_open($hostname,$username,$password) or die('Cannot connect to Gmail: ' . imap_last_error());  
// }catch(Exception e){
    // error_log("an error was encountered");
// }


/* grab emails */
$emails = imap_search($inbox,'ALL');
// var_dump($emails);
// /*Cycle through each  ... */

// var_dump($emails);
if($emails) {
    
//  /* begin output var */
    $output = '';
    
    /* put the newest emails on top */
    rsort($emails);
    
    /* for every email... */
    foreach($emails as $email_number) {
        
        /* get information specific to this email */
        $overview = imap_fetch_overview($inbox,$email_number,0);
        $message = imap_fetchbody($inbox,$email_number,2);
        
         // output the email header information 
        $output.= '<div class="toggler '.($overview[0]->seen ? 'read' : 'unread').'">';
        $output.= '<span class="subject">'.$overview[0]->subject.'</span> ';
        $output.= '<span class="from">'.$overview[0]->from.'</span>';
        $output.= '<span class="date">on '.$overview[0]->date.'</span>';
        $output.= '</div>';
        
        /* output the email body */
        $output.= '<div class="body">'.$message.'</div>';
    }
    // var_dump($output);
    // echo $output;    
}else{
    var_dump("There are no emails to be displayed ");
} 

/* close the connection */
imap_close($inbox);