如何从多个项目和数组中获取PHP中的唯一输出

PHP isn't returning unique items between assigned_IPs and IP_array. I need an unique output.

I already tried merging arrays and comparing them.

    $ips2 = array(); 

  while ($row = mysql_fetch_assoc($result))  
    {
        $ips2[] = $row["ipaddr"]; 
    } 
        $assigned_ips  = $ips2;

 $ip_array = explode("
",$ips);

$ips_left = array_diff($ip_array,$assigned_ips);

I need to return an unique array once PHP compares the 2 item lists.

Lucky for you, PHP has an array_unique() function for just such a purpose! You could perform it on both of the compared arrays before array_diff(), but I am pretty sure best (an most efficient) practice would be to perform it only once when you already have the results:

$ips2 = array(); 

  while ($row = mysql_fetch_assoc($result))  
    {
        $ips2[] = $row["ipaddr"]; 
    } 
$assigned_ips  = $ips2;

$ip_array = explode("
",$ips);

$ips_left = array_unique(
    array_diff($ip_array,$assigned_ips)
);

Just for the sake of completeness, here is an alternative way that could be more efficient if you have a large number of duplicates that would bog down the array_diff() function:

$ips2 = array(); 

  while ($row = mysql_fetch_assoc($result))  
    {
        $ips2[] = $row["ipaddr"]; 
    } 
$assigned_ips  = $ips2;

$ip_array = explode("
",$ips);

$ips_left = array_diff(
    array_unique($ip_array)
    array_unique($assigned_ips)
);