Ruby on Rails：遍历嵌套参数

Question

I want to iterate through submitted params. Params array could be up to three level. Currently I can iterate only first level like this.

params[:job].each do |v, k|
    #do something with k value, only if it's string. If it's array then find its string value.
end

How do I iterate params when you don't know what you are expecting?

Answer 1

One easy way is to use is_a?

if v.is_a? Array
  # do whatever
elsif v.is_a? String
  # do whatever
else
  # something else
end

---

Some kind of recursive solution might be best here, such as:

def handle_hash hash
  hash.each do |k, v|
    if v.is_a? Hash
      handle_hash v
    elsif v.is_a? String
      # handle string
    end
  end 
end

And then you can just call handle_hash params[:job]

Answer 2

def nested_params(nested_hash={})  
      nested_hash.each_pair do |k,v|
        case v
          when String, Fixnum then 
            dosomething(v)
          when Hash then nested_params(v)
          else raise ArgumentError, "Unhandled type #{v.class}"
        end
      end
  end