：条件声明和Ruby Rails

Question

I'm trying to get these statements to work:

@all_ratings = ["G","PG","PG-13","R"]
@valid_ratings = params["ratings"]
@movies = Movie.find(:all ,  :conditions => {@valid_ratings[:rating.upcase] => "1"}   )

but I am getting the error:

undefined method `to_sym' for nil:NilClass

when I should be getting a match.

An example input is:

"ratings"=>{"PG-13"=>"1"}

Where am I going wrong?

---

More info:

The table has three fields, the title, release date, and rating, and is very simple. The options for rating are stated above in @all_ratings .

Answer 1

It tells you that you @valid_ratings in nil

You probably trying doing this?

@valid_ratings = Rating.find(params["ratings"])

Answer 2

Rails 3.x:

@all_ratings = ["G","PG","PG-13","R"]
@valid_ratings = params["ratings"]
# Is @valid_ratings the same as you example, "ratings"=>{"PG-13"=>"1"}?
# It would be easiest to pass a subset of @all_ratings such that the params
# get converted to something like this: "ratings"=>["G", "PG"]
Movie.where(:rating => valid_ratings).all
# SQL: SELECT * FROM movies WHERE rating IN ('G','PG')

I am not sure what you are trying to with :rating.upcase . Is there a variable named rating? :rating is a symbol. upcase is not a method on Symbol.