How to pair the values of these two arrays in PHP?

I have a table with some items on it and each row has a checkbox and a textarea. When I pres submit I want to take the values of the textareas ONLY for the respective checked checkbox and NOT for the ones that aren't checked even if they have textareas with some content.

<form method="post">
                <?php if (!empty($arr_devices)) { ?>
                    <?php foreach ($arr_devices as $device) : ?>
                        <tr>
                            <td>
                                <input type="checkbox" name="devices[]" value="<?php echo $device["id"].$dev_comment ?>">
                            <td>
                           <td>  
<div class="input-group">
                                    <textarea name="dev_comment[]" placeholder="comment" rows="1" cols="50"><?php echo $dev_comment; ?></textarea>
                                </div>
                            </td>

                        </tr>
                    <?php endforeach; ?>
                <?php } ?>
                <input class="btn" type="submit" name="submit" value="Report">
                <form>

Printed arrays after summitted:

  Device_id([0] => 790 [1] => 1140 [2] => 1142 ) 
  Comments( [0] => sdf [1] => sdfsdfs [2] => [3] => fsdfsd [4] => )

as it is now, I am able to receive ONLY the device_id for the checked ones but ALL the values(even empty ones) for the comments when I am submitting. Why is that happening and how to fix it?