You cannot pass an array or a hash directly from one HTML form to another using hidden fields. A hidden field can only pass text.

If you want to pass arrays or hashes as hidden fields you must first convert the arrays and hashes to text.

If your arrays or hashes are large then after you have converted them to strings you will probably want to use the 'POST' rather than the 'GET' method to send the strings as hidden variables in your HTML forms. Some environments impose artificial limits on the length of the parameter strings that the 'GET' method produces.