Question

Hi I keep running into a problem on trying to figure how I can create lists in Rails. My problem is I have a Team object, then I have a fixture object which contains a hometeam and awayteam, I want to be able generate the fixtures automatically, e.g. I have 20 teams so each team has 38 games they need to play each team home and away, how can I create a fixtures list to meet these requirements or is it possible in Rails. By making each team play everyone at home once it will create all the away fixtures also.

Answer 1

Ruby Array has a method combination that does the job. http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-combination

Something like

teams = Team.all.to_a # or any selection of teams
teams.combination(2) do |first_team, second_team|
  Fixture.create!(hometeam: first_team, awayteam: second_team)
  Fixture.create!(hometeam: second_team, awayteam: first_team)
end

Will create all 380 fixtures for 20 teams.