Rails - Iterating through records witin a method

Question

I have a method that just iterates through various models, printing out the model attributes:

def self.get_attributes(options = {})
  options[:model_name].find(:all, :conditions => {:generated_at => options[:start_date]..options[:end_date]}).each do |p|
  puts p.options[:col_name]
end

to call the method:

start_date = DateTime.strptime(params[:start_date], '%m/%d/%Y').beginning_of_day.strftime("%Y-%m-%d %H:%M:%S")
end_date = DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day.strftime("%Y-%m-%d %H:%M:%S")
get_attributes({:model_name =>  Revenue, :col_name => "revenue",  :start_date => start_date, :end_date => end_date})

I have tried passing in the column name as a string and variable. When passed as a variable I get an undefined variable exception. As is above, I get an undefined method 'col_name' exception. How can I interpolate the column name within the above method?

Answer 1

You would represent the column/method name as a symbol (e.g. :revenue) and invoke it with __send__ as in:

p.__send__(options[:col_name])