Advanced Custom Fields - how to merge checkboxes?

Question

WordPress

There is a wordpress site using the ACF (Advanced Custom Fields) plugin - for creating custom fields in posts.
The bottom line is that there are several checkbox fields in the record, which, when displayed, I need to combine into one select field for the user. There can be many such groups of checkboxes - up to 40.
A poor way of output came to mind:

$field1 = get_field('field1');
$field2 = get_field('field2');
$field3 = get_field('field3');
...
$field40 = get_field('field40);

Get all the values ​​manually, then combine them into an array and enter from the array into the select.

$fields = array($field1,$field2..$field40);
foreach ($fields as $key => $val)
{				
echo '<option  value='.'"'.htmlspecialchars($val).'"'.' >'.$val.'</option>';
}

But 40 times I don’t want to write this at all.
Can you please tell me how this can be automated?
It is necessary somehow in the for loop (i=1;i<41;i++)..

Answer 1

$fields = array();
        for ($i = 1; $i < 40; $i++) 
          { 
          $fields[$i] = get_field('hotels'.$i);	
          } 
foreach ($fields as $key  ){
    foreach ($key as $var  )
    {
    echo '<option  value="'.$var.'">'.$var.'</option>';
    }										
}