使用PHP比较两个数组并在新数组中存储不常见的字符串

Below I have two arrays with values.

Array 1 - reorder_str

Array ( 
    [0] => A aacomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [1] => A eecomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [2] => defined 
    [3] => defined 
    [4] => defined 
) 

Array 2 -reorder1

Array ( 
    [0] => A bbcomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [1] => A cccomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [2] => A aacomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [3] => A ddcomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    [4] => A eecomputational agent is considered intelligent if it can adapt its actions to a particular setting.
)

<?php if(in_array($reorder1[0], $reorder_str)){
 ?>
    <div class="qitem di">
        1.<?php echo $reorder1[0];?>
    </div>
    <?php }?>

My expected output array3

Array ( 
        [0] => A bbcomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
        [1] => A cccomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
         [2] => A ddcomputational agent is considered intelligent if it can adapt its actions to a particular setting. 
    )

I Want to show the string if it is not present in array(reorder_str).I tried like this but its not working out. My array 3 should store Uncommon strings from two array and new show not have any empty or undefined value.Thanks in advance.Meanwhile I tried with array_diff ,in_array but I couldn't get exact answer.

Check this code as per your expected output,

$arr1 = array(
    0 => "A aacomputational agent is considered intelligent if it can adapt its actions to a particular setting.",
    1 => "A eecomputational agent is considered intelligent if it can adapt its actions to a particular setting.",
    2 => "defined ",
    3 => "defined ",
    4 => "defined ",
);
$arr1 = array_map('trim', $arr1);
$arr2 = array(
    "0" => "A bbcomputational agent is considered intelligent if it can adapt its actions to a particular setting.",  
    "1" => "A cccomputational agent is considered intelligent if it can adapt its actions to a particular setting.",  
    "2" => "A aacomputational agent is considered intelligent if it can adapt its actions to a particular setting.",  
    "3" => "A ddcomputational agent is considered intelligent if it can adapt its actions to a particular setting.",  
    "4" => "A eecomputational agent is considered intelligent if it can adapt its actions to a particular setting."
);
$arr2 = array_map('trim', $arr2);
$result = array_diff($arr2,$arr1);
print_r($result);

Here is working link