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    Set.insert vs array << x unless array.include?(x)

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    • thomthomT Offline
      thomthom
      last edited by thomthom

      I was curious of the difference between Set.insert vs array << x unless array.include?(x) when you want a collection with a unique set of values.

      So I did some tests:

      Test 1
      A 10,000,000 times I tried to insert a number between 0-10.

      t=Time.now;a=[];10000000.times{r=rand(10);a<<r unless a.include?(r)};puts Time.now - t
      Result: 12.297

      t=Time.now;a=Set.new;10000000.times{a.insert(rand(10))};puts Time.now - t
      Result: 15.719

      The array was faster here by three seconds. But that's with ten million iterations!

      Test 2
      But, when your collection of unique values increases:
      t=Time.now;a=[];100000.times{r=rand(10000);a<<r unless a.include?(r)};puts Time.now - t
      Result: 45.129

      t=Time.now;a=Set.new;100000.times{a.insert(rand(10000))};puts Time.now - t
      Result: 0.391

      When your collection include a much higher number of elements - then the Array quickly starts to crumble. In this case, when the possible unique set was up to 100,000 the difference was 44.738 seconds!!!

      I tried this in some of my scrips which on occasions require a unique set of entites (like collecting all vertices) and the speed difference was immense on larger models.

      It doesn't take too many number of unique elements before Set becomes faster then array.include?.

      Scaling
      Just to illustrate how they scale:
      Array.include?
      t=Time.now;a=[];1000.times{r=rand(100);a<<r unless a.include?(r)};puts Time.now - t
      0.0
      t=Time.now;a=[];10000.times{r=rand(1000);a<<r unless a.include?(r)};puts Time.now - t
      0.485
      t=Time.now;a=[];100000.times{r=rand(10000);a<<r unless a.include?(r)};puts Time.now - t
      42.906
      t=Time.now;a=[];1000000.times{r=rand(100000);a<<r unless a.include?(r)};puts Time.now - t
      Took too long. I guess it'd take ~4000.0s

      Set.insert
      t=Time.now;a=Set.new;1000.times{a.insert(rand(100))};puts Time.now - t
      0.0
      t=Time.now;a=Set.new;10000.times{a.insert(rand(1000))};puts Time.now - t
      0.047
      t=Time.now;a=Set.new;100000.times{a.insert(rand(10000))};puts Time.now - t
      0.422
      t=Time.now;a=Set.new;1000000.times{a.insert(rand(100000))};puts Time.now - t
      4.937

      Conclusion (not!)
      %(#aaaaaa)[Use the Set class when you require a unique set of values - unless your set of unique values is very small.
      Set class is the rule - Array.include? is the exception.]

      Update
      None of the above is the fastest. A better way has appeared. Collect everything into an array and apply [ruby:2yy3xvjs].unique![/ruby:2yy3xvjs] at the end.
      http://forums.sketchucation.com/viewtopic.php?f=180&t=23760&p=222231#p222221

      Thomas Thomassen — SketchUp Monkey & Coding addict
      List of my plugins and link to the CookieWare fund

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      • thomthomT Offline
        thomthom
        last edited by

        Also, Set.include? is faster than Array.include?

        Thomas Thomassen — SketchUp Monkey & Coding addict
        List of my plugins and link to the CookieWare fund

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        • fredo6F Offline
          fredo6
          last edited by

          Tom,

          very useful actually.
          It really looks that the processsing in C is a lot faster than in Ruby.

          Thanks

          Fredo

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          • thomthomT Offline
            thomthom
            last edited by

            @unknownuser said:

            Tom,

            very useful actually.
            It really looks that the processsing in C is a lot faster than in Ruby.

            Thanks

            Fredo

            Set class makes more processing in C?
            What I'm wondering is, the Set class in SU Ruby is not the same Set class you get in Ruby 1.8.0. The Set class in Ruby 1.8.0 includes Enumerable and the set.rb looks to be a pure ruby class that mixes arrays and hashes. From my Ruby 1.8.0. installation, the Set class seem to be a pure Ruby implementation. But maybe the Set class that comes with SU is a C implementation...? Maybe that's why they replaced it?

            Thomas Thomassen — SketchUp Monkey & Coding addict
            List of my plugins and link to the CookieWare fund

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            • thomthomT Offline
              thomthom
              last edited by

              I thought the speed difference was that the Set class used a more efficient Hash lookup as oppose to the Array functions that has to iterate the array every time... but that's just guesswork...

              Thomas Thomassen — SketchUp Monkey & Coding addict
              List of my plugins and link to the CookieWare fund

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              • fredo6F Offline
                fredo6
                last edited by

                @thomthom said:

                I thought the speed difference was that the Set class used a more efficient Hash lookup as oppose to the Array functions that has to iterate the array every time... but that's just guesswork...

                You're right.
                I personally use Hash whenever I want to store lists that have unique elements.
                The list itself is obtained via Hash.values.

                Maybe, as you are on this, you extend your benchmark to Hash and see how it compares with Set.

                Fred

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                • Chris FullmerC Offline
                  Chris Fullmer
                  last edited by

                  Great info Thom! I had played around with sets and arrays before and I was not impressed with sets. But I did not experiment with amount of unique objects, which apparently has an adverse effect on arrays. Thanks,

                  Chris

                  Lately you've been tan, suspicious for the winter.
                  All my Plugins I've written

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                  • thomthomT Offline
                    thomthom
                    last edited by

                    @unknownuser said:

                    Will have a look

                    Will have a look at that.

                    Thomas Thomassen — SketchUp Monkey & Coding addict
                    List of my plugins and link to the CookieWare fund

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                    • thomthomT Offline
                      thomthom
                      last edited by

                      I'll be damned!
                      Very interesting Jernej.

                      ...looks like I need to do some more testing of my script and possibly refactor again.

                      So while the Array.include? is dead slow - the overhead of hash look-up is still faster than just adding everything into one big pile and so a single filtering afterwards...

                      Thomas Thomassen — SketchUp Monkey & Coding addict
                      List of my plugins and link to the CookieWare fund

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                      • thomthomT Offline
                        thomthom
                        last edited by

                        looking at the .uniq! source code: http://ruby-doc.org/core/classes/Array.src/M002215.html

                        
                        /*
                         *  call-seq;
                         *     array.uniq! -> array or nil
                         *  
                         *  Removes duplicate elements from _self_.
                         *  Returns <code>nil</code> if no changes are made (that is, no
                         *  duplicates are found).
                         *     
                         *     a = [ "a", "a", "b", "b", "c" ]
                         *     a.uniq!   #=> ["a", "b", "c"]
                         *     b = [ "a", "b", "c" ]
                         *     b.uniq!   #=> nil
                         */
                        
                        static VALUE
                        rb_ary_uniq_bang(ary)
                            VALUE ary;
                        {
                            VALUE hash, v, vv;
                            long i, j;
                        
                            hash = ary_make_hash(ary, 0);
                        
                            if (RARRAY(ary)->len == RHASH(hash)->tbl->num_entries) {
                                return Qnil;
                            }
                            for (i=j=0; i<RARRAY(ary)->len; i++) {
                                v = vv = rb_ary_elt(ary, i);
                                if (st_delete(RHASH(hash)->tbl, (st_data_t*)&vv, 0)) {
                                    rb_ary_store(ary, j++, v);
                                }
                            }
                            RARRAY(ary)->len = j;
                        
                            return ary;
                        }
                        
                        

                        Thomas Thomassen — SketchUp Monkey & Coding addict
                        List of my plugins and link to the CookieWare fund

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                        • thomthomT Offline
                          thomthom
                          last edited by

                          Jernej: how about larger iterations and higher number of random values?

                          Thomas Thomassen — SketchUp Monkey & Coding addict
                          List of my plugins and link to the CookieWare fund

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                          • J Offline
                            Jernej Vidmar
                            last edited by

                            How about using Array.uniq! method:

                            Test 1
                            t=Time.now;a=[];10000000.times{r=rand(10);a<<r unless a.include?(r)};puts Time.now - t
                            Result: 12.297
                            t=Time.now;a=Set.new;10000000.times{a.insert(rand(10))};puts Time.now - t
                            Result: 15.719
                            t=Time.now;a=[];10000000.times{r=rand(10);a<<r};a.uniq!; puts Time.now - t
                            Result: 7.753

                            Test 2
                            t=Time.now;a=[];100000.times{r=rand(10000);a<<r unless a.include?(r)};puts Time.now-t
                            Result: 40.97
                            t=Time.now;a=Set.new;100000.times{a.insert(rand(10000))};puts Time.now-t
                            Result: 0.377
                            t=Time.now;a=[];100000.times{r=rand(10000);a<<r};a.uniq!;puts Time.now-t
                            Result: 0.087

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                            • J Offline
                              Jernej Vidmar
                              last edited by

                              @thomthom said:

                              Jernej: how about larger iterations and higher number of random values?

                              t=Time.now;a=Set.new;10000000.times{a.insert(rand(10000))};puts Time.now - t
                              Result: 37.911
                              t=Time.now;a=[];10000000.times{r=rand(10000);a<<r};a.uniq!; puts Time.now - t
                              Result: 8.282

                              Still a winner?

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                              • thomthomT Offline
                                thomthom
                                last edited by

                                It's refactoring time!

                                Nice find! 👍

                                Thomas Thomassen — SketchUp Monkey & Coding addict
                                List of my plugins and link to the CookieWare fund

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                                • R Offline
                                  RickW
                                  last edited by

                                  That's all great (using .uniq!) until you start dealing with Point3d objects 😄
                                  In that case, always use Set.

                                  RickW
                                  [www.smustard.com](http://www.smustard.com)

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                                  • TIGT Offline
                                    TIG Moderator
                                    last edited by

                                    ....or make all of your Point3d's into arrays so they will sort!/uniq! etc as arrays...

                                    TIG

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                                    • thomthomT Offline
                                      thomthom
                                      last edited by

                                      @tig said:

                                      ....or make all of your Point3d's into arrays so they will sort!/uniq! etc as arrays...

                                      But is the overhead of converting the Point3d's into arrays and uniq! faster than using a Set?

                                      Thomas Thomassen — SketchUp Monkey & Coding addict
                                      List of my plugins and link to the CookieWare fund

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                                      • TIGT Offline
                                        TIG Moderator
                                        last edited by

                                        Who knows ?
                                        Time for you to do another test... 😉

                                        TIG

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                                        • honoluludesktopH Offline
                                          honoluludesktop
                                          last edited by

                                          I probably don't know what I am doing, but I ran the following test, and obtained the attached results. I typically use array.push variable, and don't understand the situations when the other examples might be used. Btw, when I applied the other forms to my app, it failed in ways that leave me to believe that those forms are data sensitive. Can anyone explaine to a Ruby beginner what's up?

                                          t=Time.now
                                          a=[]
                                          100000.times do r=rand(10000)
                                            a<<r
                                          end
                                          a.uniq!
                                          puts Time.now-t
                                          

                                          0.125

                                          t=Time.now
                                          a=[]
                                          100000.times do r=rand(10000)
                                            a.push r
                                          end
                                          a.uniq!
                                          puts Time.now-t
                                          

                                          0.141

                                          t=Time.now
                                          a=[]
                                          100000.times do r=rand(10000)
                                            a.push r
                                          end
                                          puts Time.now-t
                                          

                                          0.094

                                          t=Time.now
                                          a=[]
                                          100000.times do r=rand(10000)
                                            a<<r
                                          end
                                          puts Time.now-t
                                          

                                          0.093

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