我正试图让这些语句发挥作用:
@all_ratings = ["G","PG","PG-13","R"]
@valid_ratings = params["ratings"]
@movies = Movie.find(:all , :conditions => {@valid_ratings[:rating.upcase] => "1"} )
但我得到了错误:
undefined method `to_sym' for nil:NilClass
当我应该得到一场比赛。
示例输入是:
"ratings"=>{"PG-13"=>"1"}
我哪里错了?
更多信息:
该表有三个字段,标题、发布日期和评级,非常简单。评级选项如上文@all_ratings
所述。
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')
我不确定你想用:rating.upcase
做什么。是否有一个名为评级的变量?CCD_ 3是一个符号。upcase
不是Symbol上的方法。
它告诉您nil
中的@valid_ratings
你可能想这么做?
@valid_ratings = Rating.find(params["ratings"])