Title: Group codes
Last modified: February 13, 2019

---

# Group codes

 *  Resolved [funsail](https://wordpress.org/support/users/funsail/)
 * (@funsail)
 * [7 years, 3 months ago](https://wordpress.org/support/topic/group-codes-2/)
 * Why does the plugin generate code like
 * `<input name="INTERESTS[b2f7932c76][]" value="41c5e1d14b" checked="true" type
   ="checkbox">`
 * but MP form builder generates
 * `<input type="checkbox" value="1024" name="group[13721][1024]" id="mce-group[
   13721]-13721-0">`
 * And then it seems to work in CF7 using
 *     ```
       <input type="hidden" name="mc4wp-INTERESTS[b2f7932c76]" value="Yes">
       ```
   

Viewing 4 replies - 1 through 4 (of 4 total)

 *  Thread Starter [funsail](https://wordpress.org/support/users/funsail/)
 * (@funsail)
 * [7 years, 3 months ago](https://wordpress.org/support/topic/group-codes-2/#post-11200078)
 * I get you add mc4wp-
    but what is the extra [] in INTERESTS[b2f7932c76][] Why
   do neither use the field name like in [https://kb.mc4wp.com/send-additional-cf7-fields-mailchimp/](https://kb.mc4wp.com/send-additional-cf7-fields-mailchimp/)
 * Why do neither use a text value?
 *  Plugin Contributor [Harish Chouhan](https://wordpress.org/support/users/hchouhan/)
 * (@hchouhan)
 * [7 years, 3 months ago](https://wordpress.org/support/topic/group-codes-2/#post-11201211)
 * Hello,
 * Thanks for reaching out to us.
 * The extra “[]” sign is used because the Interest groups are processed as an array
   in PHP. We used to as earlier in some cases the details are not sent to MailChimp
   in some integrations. Hence we decided to use it so it works in most use cases.
   If it’s working for you without using those extra characters, then you are free
   to remove them.
 *  Thread Starter [funsail](https://wordpress.org/support/users/funsail/)
 * (@funsail)
 * [7 years, 3 months ago](https://wordpress.org/support/topic/group-codes-2/#post-11204686)
 * I see. And when an existing user signs up I find that the
 * <input name=”INTERESTS[b2f7932c76][]” value=”41c5e1d14b” checked=”true” type=”
   checkbox”>
 * doesn’t take effect. What can we do?
 *  Plugin Contributor [Harish Chouhan](https://wordpress.org/support/users/hchouhan/)
 * (@hchouhan)
 * [7 years, 2 months ago](https://wordpress.org/support/topic/group-codes-2/#post-11222513)
 * Hello,
 * Have you placed this code in our plugin or 3rd party form?

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Group codes’ is closed to new replies.

 * ![](https://ps.w.org/mailchimp-for-wp/assets/icon-256x256.png?rev=1224577)
 * [MC4WP: Mailchimp for WordPress](https://wordpress.org/plugins/mailchimp-for-wp/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/mailchimp-for-wp/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/mailchimp-for-wp/)
 * [Active Topics](https://wordpress.org/support/plugin/mailchimp-for-wp/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/mailchimp-for-wp/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/mailchimp-for-wp/reviews/)

 * 4 replies
 * 2 participants
 * Last reply from: [Harish Chouhan](https://wordpress.org/support/users/hchouhan/)
 * Last activity: [7 years, 2 months ago](https://wordpress.org/support/topic/group-codes-2/#post-11222513)
 * Status: resolved