I''m trying to randomize an array, and this is what I have:
arr_set_unordered = randomizer(arr_set)
def randomizer(arr)
result = arr.collect { arr.slice!(rand arr.length) }
end
It does randomize it, but it only returns 3 values instead of the
necessary 5 that are in the arr_set array. Any ideas why?
Thank you!
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---
Please try: http://www.google.com/search?rls=en&q=array+shuffle+ruby -Rob On Dec 22, 2006, at 4:51 AM, jwcooper wrote:> > I''m trying to randomize an array, and this is what I have: > > arr_set_unordered = randomizer(arr_set) > > def randomizer(arr) > result = arr.collect { arr.slice!(rand arr.length) } > end > > > It does randomize it, but it only returns 3 values instead of the > necessary 5 that are in the arr_set array. Any ideas why? > > Thank you!Rob Biedenharn http://agileconsultingllc.com Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Just to save you a little time:>> myarr = [1,2,3,4,5]=> [1, 2, 3, 4, 5]>> myarr.sort_by { rand }=> [5, 3, 2, 4, 1] --Jeremy On 12/22/06, jwcooper <jwcooper-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> > I''m trying to randomize an array, and this is what I have: > > arr_set_unordered = randomizer(arr_set) > > def randomizer(arr) > result = arr.collect { arr.slice!(rand arr.length) } > end > > > It does randomize it, but it only returns 3 values instead of the > necessary 5 that are in the arr_set array. Any ideas why? > > Thank you! > > > > >-- My free Ruby e-book: http://www.humblelittlerubybook.com/book/ My blogs: http://www.mrneighborly.com/ http://www.rubyinpractice.com/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Jeremy McAnally wrote:> Just to save you a little time: > >>> myarr = [1,2,3,4,5] > => [1, 2, 3, 4, 5] >>> myarr.sort_by { rand } > => [5, 3, 2, 4, 1] > > --Jeremy >This doesn''t seem to belong in a rails discussion, but I was curious and looked at performance. It seems the elegant ways are not the best. See ruby code below. Stephan # Timing different way to shuffle an array in ruby class Array # The ruby way of swapping two variable values def swap!(a,b) self[a], self[b] = self[b], self[a] end # the "assembler" way of swapping two variable values def swap_with_int_var!(a,b) c = self[a] self[a] = self[b] self[b] = c end # Shuffling arrays is usually done by iterating through the indices, and swapping # each value with a value at a random position # shuffling based on push/delete def shuffle! size.downto(1) { |n| push delete_at(rand(n)) } self end # shuffling with the ruby way of swapping def shuffle_II (size-1).downto(1) { |n| swap!(n, rand(size)) } self end # shuffling with the "assembler" way of swapping def shuffle_III (size-1).downto(1) { |n| swap_with_int_var!(n, rand(size)) } self end def shuffle_IV sort_by { rand } end end def time_shuffle_method(size) a = (0..size).to_a start_time = Time.new 3000.times { yield a } end_time = Time.new return end_time - start_time end # To inspect shuffling methods, invoke with argument "test" and optionally, size if (ARGV[0] == ''test'') size = ARGV[1] ? ARGV[1].to_i : 5 puts (0..size).to_a.shuffle! puts ''--'' puts (0..size).to_a.shuffle_II puts ''--'' puts (0..size).to_a.shuffle_III puts ''--'' puts (0..size).to_a.shuffle_IV exit end shuffle_time = time_shuffle_method(500) { |a| a.shuffle! } puts "Time elapsed for shuffle! : #{shuffle_time}" shuffle_time_II = time_shuffle_method(500) { |a| a.shuffle_II } puts "Time elapsed for shuffle_II : #{shuffle_time_II}" shuffle_time_III = time_shuffle_method(500) { |a| a.shuffle_III } puts "Time elapsed for shuffle_III : #{shuffle_time_III}" shuffle_time_IV = time_shuffle_method(500) { |a| a.shuffle_IV } puts "Time elapsed for shuffle_IV : #{shuffle_time_IV}" =begin Here are results from running on my machine Conclusion: fancy ruby manipulations take their time Stick with the "ordinary" shuffle implementation ( shuffle_III ) stephan@[/tmp]: ruby shuffle_timer Time elapsed for shuffle! : 4.319548 Time elapsed for shuffle_II : 5.956232 Time elapsed for shuffle_III : 3.011474 Time elapsed for shuffle_IV : 3.672521 stephan@[/tmp]: ruby shuffle_timer Time elapsed for shuffle! : 4.30994 Time elapsed for shuffle_II : 5.902858 Time elapsed for shuffle_III : 3.139915 Time elapsed for shuffle_IV : 3.692018 Stephan Wehner January 2007 =end -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Very cool, and very useful information. I appreciate everyones help in this! I did a lot of searching on google, but came up empty, so I am thankful for this help. My situation isn''t extremely time sensitive, but I''m glad to know a simple solution such as the 3rd, or 4th option will work well. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---