CODEWITHSUNDEEP
ruby-on-railsrubydynamic
MorningHacker
MorningHacker

Reputation: 1204

how to create dynamic variables in rails function?

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?

Upvotes: 3

Views: 4836

Answers (4)

Samuel Müller
Samuel Müller

Reputation: 1217

you should do something like this:

def setup
  @reading_img    = get_img(whatever)
  @reading_link   = get_link(whatever)
  @listening_img  = get_img(whatever)
  @listening_link = get_link(whatever)
end

def get_img(whatever)
  ...do stuff and return stuff...
end

def get_link(whatever)
  ...do stuff and return stuff...
end

Upvotes: 1

recursive
recursive

Reputation: 494

Good looking out trying to dry up your code. I would definitely use some hashes there instead of instance variables. Then you can use the key as the action. Just a thought.

Upvotes: 4

sameera207
sameera207

Reputation: 16629

IMPO, I think you should use more generic variables. Although the creating variables are supported by ruby, it will make your code hard to read

my suggestion is having some generic names like

@img (instead of reading_img, listing_img etc..) @link (instead of reading_link, listing_link etc..) and something like @content, because as your login at a given time only one will be selected and this wouldn't be a problem

Again, this is what i understood from the code you posted and correct me if I'm wrong

cheers

sameera

Upvotes: 1

Steve Ross
Steve Ross

Reputation: 4144

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...

Upvotes: 6

Related Questions