Sort collection of object in rails ?

Question

I know I can use something like User.sort {|a, b| a.attribute <=> b.attribute} or User.find and order, but is it a way like comparable interface in Java, so every time I called sort on User object it will do sort on the predefined attributes.

Thanks,

Answer 1

You can do that by defining the <=> method for your objects. That way, you should be able to just say: collection.sort for non-destructive sort, or collection.sort! for in-place sorting:

So, example here:

class A
   def <=>(other)
      # put sorting logic here
   end
end

And a more complete one:

class A
    attr_accessor :val
    def initialize
       @val = 0
    end

    def <=>(other)
       return @val <=> other.val
    end
end

a = A.new
b = A.new
a.val = 5
b.val = 1
ar = [a,b]
ar.sort!
ar.each do |x|
  puts x.val
end

This will output 1 and 5.