如果值不存在，则插入cookie

I am trying to insert cookie. The logic is simple as:

• Check if the value is present .
• If not, insert new value with comma separated form.

I have tried some code but I could not able to get a correct result.

In this code a new value should be inserted, which is happening but not getting old value.

Edited Code 2

        $current_value = '';
 if(!isset($_COOKIE['blog_id_cookie'])){
     setcookie('blog_id_cookie', $id);
     $current_value[] = $_COOKIE['blog_id_cookie'];
 } else {
     $current_value = explode(',', $_COOKIE['blog_id_cookie']);
 } 
 if(!in_array($id, $current_value)){
     $current_value[] = $id;
     $cookie_name  = "blog_id_cookie";
     setcookie($cookie_name, implode(',', $current_valu));
 }

With that code $current_value will be defined only if the cookies is not set. Set $current_value in the else part. Concatenate the cookie instead of $current_value. Try with -

Update

 $current_value = '';
 if(!isset($_COOKIE['blog_id_cookie'])){
     setcookie('blog_id_cookie', $id);
     $current_value[] = $_COOKIE['blog_id_cookie'];
 } else {
     $current_value = explode(',', $_COOKIE['blog_id_cookie']);
 } 
 if(!in_array($id, $current_value)){
     $current_value[] = $id;
     $cookie_name  = "blog_id_cookie";
     setcookie($cookie_name, implode(',', $current_value));
 }