Multiple Sorts on an array, help with bad code smell

rubyonrails-talk
1

I have an Array of active record objects that I need to sort by two attributes: similarity and activity, both are integers.

I’m currently doing this by first sorting the array on the similarity field, and then using group_by to group them groups with the same ‘similarity’ and then sorting those groups by activity. Flattening this whole thing our returns the original list sorted first by similarity and then by activity.

Problem, this code is ugly, there has to be a cleaner way to do this. Here is the full method, its from a ActiveRecord model called ‘Group’.

http://pastie.caboo.se/70645

def related_groups #get the tags for this group tag_string = tags.collect(&:name) #find other groups with same tags

groups_with_same_tags = Group.find_tagged_with(tag_string)
if groups_with_same_tags.any?
  #delete self from list of groups

  groups_with_same_tags.delete(self)
  #delete duplicates
  groups_with_same_tags.uniq!
  #count how many tags they have in common (probably could cleanup with inject)

  groups_with_same_tags.each do |group|
    group.similarity = 0
     tags.each

do |tag| group.similarity = group.similarity + 1 if group.tags.include?(tag) end end #sort based on similarity of tags groups_with_same_tags = groups_with_same_tags.sort{ |x,y| y.similarity <=> x.similarity } #group into a 2D array grouped by similarity, make sure to preserve priority of the similarity

  grouped_groups = groups_with_same_tags.group_by(&:similarity).sort{|x,y| y[0] <=> x[0]}

  #sort the 2nd dimension of the array(which is an array of the items of a specific similarity) based on activity

   sorted_groups = grouped_groups.collect{ |g| g[1].sort{|x,y| y.activity <=> x.activity

}} #flatten it out into a 1D array and return sorted_groups.flatten! else end end

Thanks!

2

Steve - Unfortunately not, activity is not stored in the database. It is a dynamic tally of how many tags it has in common with the original object.

thanks

3

Try something like:

groups_with_same_tags.sort! { |a, b| a.similarity == b.similarity ? b.activity <=> a.activity : b.similarity <=> a.similarity }

4

perfect, tests pass, thanks!

5

No problem--glad it worked.