Question

I have this code that’s working:

  case index
   when "Books"
     @reading_img = res.items.first.get_hash('MediumImage')["URL"] # don't show an image
     @reading_link = create_amz_url(search, asin)        

     tempy = @nowreading.content.match(/#nowreading.*/).to_s.gsub("#nowreading",'') # strips away the #nowreading tag
     @nowreading.content = tempy.match(/#{search}.*/).to_s.gsub("#{search}", @reading_link) 
     # replaces the book title (passed in as variable 'search') with the URL'ed title

   when "Music"
     @listening_img = res.items.first.get_hash('MediumImage')["URL"] # don't show an image
     @listening_link = create_amz_url(search, asin)        

     tempy = @nowlistening.content.match(/#nowlistening.*/).to_s.gsub("#nowlistening",'') # strips away the #nowreading tag
     @nowlistening.content = tempy.match(/#{search}.*/).to_s.gsub("#{search}", @listening_link) 
     # replaces the song title (passed in as variable 'search') with the URL'ed title       

   end

I need to repeat this for many, many categories. I tried something like this to DRY the code but it didn’t work:

     def get_img_and_links(act, res, search, asin)
        '@'+act+'ing_img' = res.items.first.get_hash('MediumImage')["URL"] # don't show an image
        '@'+act+'ing_link' = create_amz_url(search, asin)        

        tempy = '@now'+act+'ing'.content.match(/#now"#{act}"ing.*/).to_s.gsub("#now#{act}ing",'') # strips away the #nowreading tag
        '@now'+act+'ing'.content = tempy.match(/#{search}.*/).to_s.gsub("#{search}", '@'+act+'ing_link') 
        # replaces the book title (passed in as variable 'search') with the URL'ed title
     end

Essentially, I was trying to create a function that took an “act” (e.g., “read”, “listen”, etc) and have the variables within that function be dynamic. Can this be accomplished? If so, how?

Answer 1

Look up instance_variable_set here: http://ruby-doc.org/core/classes/Object.html. It’s what you need to dynamically create these variables.

instance_variable_set "@#{act}ing_img".to_sym, res.items.first.get_hash('MediumImage')["URL"]

And so on…