If you want to add additional parameters to a link using a path helper, for example for nested restful resources, it is useful to use a hash. All additional parameters are added to the query string:
group_post_path(:group_id => group, :id => post) >> /groups/4/posts/2 group_post_path(:group_id => group, :id => post, :option => 1) >> /groups/4/posts/2?option=1
If you use an array or list instead, then you must specify the exact number of arguments and can not pass additional parameters:
group_post_path(group,post)
4 Lines of Code 