Validation for dynamic radio buttons Laravel 5

I want to validate my dynamic radio inputs. I have this in my view view.blade.php:

echo "<span class='error'>".$errors->first('sar')."</span><td></tr>";

for($i=1; $i<11; $i++){
echo"<td>"; ?>
<input class='radio-inline' name='sar[<?php echo $number; ?>]' type='radio' value='<?php echo $i; ?>' ><?php    echo "</td>";} 

Controller:

//valida pontas -- 
$this->validate($request, [
    'sar' => 'required'
]);

I have tried: inside view $vf = 'sar['.$fcid.']'; $errors->first($vf) and inside my controller: 'sar[$i]' => 'required'

So the for loop dynamically creates radio buttons with names like 'sar[1]' in my this validate i dont know how I would validate each dynamically created radio input... Any ideas on how to approach this would be greatly appreciated..

via Chebli Mohamed