Rails: How to initialize instance variable in new action -


i have 2 models post , comments.

class post < activerecord::base  has_many :comments  end  class comment < activerecord::base  belongs_to :post end

my form creating new comment below

<%= form_for @comment , :url => post_comments_path(params[:post_id])  |f| %>     <%= f.text_area :title %>     <%= f.submit "add comment" %> <% end %>

i having confusion new action of above form. in new action can initialize @comment instance variable below 2 ways.

@comment = comment.new  or   @post = post.find(params[:id) @comment = @post.comments.build(set_params)

my question difference between comment.new , @post.comments.build(set_params).

the latter preferred, because set post_id on comment.


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